Curriculum›4B›Chapter 12

Chapter 12: worked solutions and marking guide

40 review answers and 40 exam answers

Chapter review solutions

Question 1 · number bond

How many tenths must be added to 0.3 to make one whole?

Answer: 7 tenths

One whole is 10 tenths. Subtract 3 from 10 to find the missing parts.

Question 2 · numberline

On a number line from 0 to 1 divided into ten equal intervals, what decimal is at the 8th tick after 0?

Answer: 0.8

Each interval is 0.1, so add 8 tenths to 0 to get 0.8.

Question 3 · representation

Write 14/100 as a two-decimal-place number.

100-square whole
Answer: 0.14

14 hundredths are 0.14.

Question 4 · equivalent decimal

Rename 0.6 as hundredths and write the equivalent decimal to two places.

Answer: 60/100 = 0.60

Every tenth is ten hundredths; multiply the count by ten.

Question 5 · fraction

Write 0.14 as a fraction in simplest form.

Answer: 7/50

0.14 = 14/100. Reduce by the common factor 2 to 7/50.

Question 6 · decimal

Write 18/25 as a decimal.

Answer: 0.72

Rename 18/25 in tenths or hundredths (or divide numerator by denominator) to get 0.72.

Question 7 · comparison

Insert <, > or =: 0.63 ___ 0.91.

Answer: <

Compare 63 hundredths and 91 hundredths; 0.63 is less relative to 0.91.

Question 8 · rounding

Round 6.31 to the nearest tenth.

Answer: 6.3

Use the two neighboring nearest tenth benchmarks, identify their midpoint, and round the original number 6.31 directly.

Question 9 · representation

Write 4/10 as a decimal and explain its tenths digit.

One whole split into ten tenths
Answer: 0.4

4 equal tenths of the same whole are written 0.4.

Question 10 · numberline

On a number line from 5 to 6 divided into ten equal intervals, what decimal is at the 2nd tick after 5?

Answer: 5.2

Each interval is 0.1, so add 2 tenths to 5 to get 5.2.

Question 11 · representation

Write 70/100 as a two-decimal-place number.

100-square whole
Answer: 0.70

70 hundredths are 0.70.

Question 12 · equivalent decimal

How many hundredths are in 2 tenths?

Answer: 20 hundredths

Each tenth consists of 10 hundredths; 2×10=20.

Question 13 · fraction

Write 0.09 as a fraction in simplest form.

Answer: 9/100

0.09 = 9/100. Reduce by the common factor 1 to 9/100.

Question 14 · decimal

Write 3/4 as a decimal.

Answer: 0.75

Rename 3/4 in tenths or hundredths (or divide numerator by denominator) to get 0.75.

Question 15 · comparison

Insert <, > or =: 0.76 ___ 0.41.

Answer: >

Compare 76 hundredths and 41 hundredths; 0.76 is greater relative to 0.41.

Question 16 · rounding

Round 1.15 to the nearest tenth.

Answer: 1.2

Use the two neighboring nearest tenth benchmarks, identify their midpoint, and round the original number 1.15 directly.

Question 17 · number bond

How many tenths must be added to 0.6 to make one whole?

Answer: 4 tenths

One whole is 10 tenths. Subtract 6 from 10 to find the missing parts.

Question 18 · numberline

On a number line from 3 to 4 divided into ten equal intervals, what decimal is at the 6th tick after 3?

Answer: 3.6

Each interval is 0.1, so add 6 tenths to 3 to get 3.6.

Question 19 · representation

Write 65/100 as a two-decimal-place number.

100-square whole
Answer: 0.65

65 hundredths are 0.65.

Question 20 · equivalent decimal

Rename 0.8 as hundredths and write the equivalent decimal to two places.

Answer: 80/100 = 0.80

Every tenth is ten hundredths; multiply the count by ten.

Question 21 · fraction

Write 0.76 as a fraction in simplest form.

Answer: 19/25

0.76 = 76/100. Reduce by the common factor 4 to 19/25.

Question 22 · decimal

Write 1/2 as a decimal.

Answer: 0.5

Rename 1/2 in tenths or hundredths (or divide numerator by denominator) to get 0.5.

Question 23 · comparison

Insert <, > or =: 0.49 ___ 0.39.

Answer: >

Compare 49 hundredths and 39 hundredths; 0.49 is greater relative to 0.39.

Question 24 · rounding

Round 2.33 to the nearest whole number.

Answer: 2

Use the two neighboring nearest whole number benchmarks, identify their midpoint, and round the original number 2.33 directly.

Question 25 · number bond

How many tenths must be added to 0.4 to make one whole?

Answer: 6 tenths

One whole is 10 tenths. Subtract 4 from 10 to find the missing parts.

Question 26 · numberline

On a number line from 3 to 4 divided into ten equal intervals, what decimal is at the 1st tick after 3?

Answer: 3.1

Each interval is 0.1, so add 1 tenths to 3 to get 3.1.

Question 27 · representation

Write 23/100 as a two-decimal-place number.

100-square whole
Answer: 0.23

23 hundredths are 0.23.

Question 28 · equivalent decimal

Rename 0.4 as hundredths and write the equivalent decimal to two places.

Answer: 40/100 = 0.40

Every tenth is ten hundredths; multiply the count by ten.

Question 29 · fraction

Write 0.42 as a fraction in simplest form.

Answer: 21/50

0.42 = 42/100. Reduce by the common factor 2 to 21/50.

Question 30 · decimal

Write 3/5 as a decimal.

Answer: 0.6

Rename 3/5 in tenths or hundredths (or divide numerator by denominator) to get 0.6.

Question 31 · comparison

Insert <, > or =: 0.85 ___ 0.14.

Answer: >

Compare 85 hundredths and 14 hundredths; 0.85 is greater relative to 0.14.

Question 32 · rounding

Round 1.60 to the nearest whole number.

Answer: 2

Use the two neighboring nearest whole number benchmarks, identify their midpoint, and round the original number 1.60 directly.

Question 33 · reasoning

Write 3/10 as a decimal and explain its tenths digit. Explain how place value or a model can check your result.

One whole split into ten tenths
Answer: 0.3

3 equal tenths of the same whole are written 0.3. A correct explanation should name the relevant fractional place values and verify the answer.

Question 34 · reasoning

On a number line from 4 to 5 divided into ten equal intervals, what decimal is at the 7th tick after 4? Explain how place value or a model can check your result.

Answer: 4.7

Each interval is 0.1, so add 7 tenths to 4 to get 4.7. A correct explanation should name the relevant fractional place values and verify the answer.

Question 35 · reasoning

Write 88/100 as a two-decimal-place number. Explain how place value or a model can check your result.

100-square whole
Answer: 0.88

88 hundredths are 0.88. A correct explanation should name the relevant fractional place values and verify the answer.

Question 36 · reasoning

How many hundredths are in 1 tenth? Explain how place value or a model can check your result.

Answer: 10 hundredths

Each tenth consists of 10 hundredths; 1×10=10. A correct explanation should name the relevant fractional place values and verify the answer.

Question 37 · reasoning

Write 0.22 as a fraction in simplest form. Explain how place value or a model can check your result.

Answer: 11/50

0.22 = 22/100. Reduce by the common factor 2 to 11/50. A correct explanation should name the relevant fractional place values and verify the answer.

Question 38 · reasoning

Write 3/4 as a decimal. Explain how place value or a model can check your result.

Answer: 0.75

Rename 3/4 in tenths or hundredths (or divide numerator by denominator) to get 0.75. A correct explanation should name the relevant fractional place values and verify the answer.

Question 39 · reasoning

Order 0.63, 0.77, and 0.17 from least to greatest. Explain how place value or a model can check your result.

Answer: 0.17, 0.63, 0.77

Convert all to hundredths and sort the integer counts. A correct explanation should name the relevant fractional place values and verify the answer.

Question 40 · reasoning

Round 8.93 to the nearest whole number. Explain how place value or a model can check your result.

Answer: 9

Use the two neighboring nearest whole number benchmarks, identify their midpoint, and round the original number 8.93 directly. A correct explanation should name the relevant fractional place values and verify the answer.

Practice examination solutions

Question 1 · decimal · 2 points

Write 5/10 as a decimal.

Answer: 0.5

Rename 5/10 in tenths or hundredths (or divide numerator by denominator) to get 0.5.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 2 · reasoning · 3 points

Write 2 tenths and 1 hundredth as one decimal. Explain how place value or a model can check your result.

Answer: 0.21

2 tenths is 20 hundredths, plus 1 more makes 21 hundredths. A correct explanation should name the relevant fractional place values and verify the answer.

Scoring (3 points): 1 point for identifying the relevant property; 1 for a correct solution; 1 for reasoning.

Question 3 · equivalent decimal · 2 points

How many hundredths are in 4 tenths?

Answer: 40 hundredths

Each tenth consists of 10 hundredths; 4×10=40.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 4 · numberline · 2 points

On a number line from 1 to 2 divided into ten equal intervals, what decimal is at the 4th tick after 1?

Answer: 1.4

Each interval is 0.1, so add 4 tenths to 1 to get 1.4.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 5 · decimal · 2 points

Write 14/20 as a decimal.

Answer: 0.7

Rename 14/20 in tenths or hundredths (or divide numerator by denominator) to get 0.7.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 6 · representation · 2 points

Write 47/100 as a two-decimal-place number.

100-square whole
Answer: 0.47

47 hundredths are 0.47.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 7 · representation · 2 points

Write 78/100 as a two-decimal-place number.

100-square whole
Answer: 0.78

78 hundredths are 0.78.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 8 · rounding · 2 points

Round 9.67 to the nearest tenth.

Answer: 9.7

Use the two neighboring nearest tenth benchmarks, identify their midpoint, and round the original number 9.67 directly.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 9 · fraction · 2 points

Write 0.20 as a fraction in simplest form.

Answer: 1/5

0.20 = 20/100. Reduce by the common factor 20 to 1/5.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 10 · decimal · 2 points

Write 12/20 as a decimal.

Answer: 0.6

Rename 12/20 in tenths or hundredths (or divide numerator by denominator) to get 0.6.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 11 · reasoning · 3 points

Explain why the decimal 0.4 is the same quantity as 4 tenths.

Answer: They both represent 4 of ten equal parts

A decimal tenths digit counts the same equal parts as numerator 4 over denominator 10.

Scoring (3 points): 1 point for identifying the relationship; 1 point for the correct working or figure; 1 point for a justified answer.

Question 12 · comparison · 2 points

Insert <, > or =: 0.67 ___ 0.41.

Answer: >

Compare 67 hundredths and 41 hundredths; 0.67 is greater relative to 0.41.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 13 · representation · 2 points

Write 98/100 as a two-decimal-place number.

100-square whole
Answer: 0.98

98 hundredths are 0.98.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 14 · comparison · 2 points

Insert <, > or =: 0.57 ___ 0.25.

Answer: >

Compare 57 hundredths and 25 hundredths; 0.57 is greater relative to 0.25.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 15 · rounding · 2 points

Round 4.69 to the nearest whole number.

Answer: 5

Use the two neighboring nearest whole number benchmarks, identify their midpoint, and round the original number 4.69 directly.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 16 · comparison · 2 points

Insert <, > or =: 0.51 ___ 0.49.

Answer: >

Compare 51 hundredths and 49 hundredths; 0.51 is greater relative to 0.49.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 17 · comparison · 2 points

Insert <, > or =: 0.16 ___ 0.13.

Answer: >

Compare 16 hundredths and 13 hundredths; 0.16 is greater relative to 0.13.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 18 · reasoning · 3 points

On a number line from 3 to 4 divided into ten equal intervals, what decimal is at the 3rd tick after 3? Explain how place value or a model can check your result.

Answer: 3.3

Each interval is 0.1, so add 3 tenths to 3 to get 3.3. A correct explanation should name the relevant fractional place values and verify the answer.

Scoring (3 points): 1 point for identifying the relevant property; 1 for a correct solution; 1 for reasoning.

Question 19 · numberline · 2 points

On a number line from 2 to 3 divided into ten equal intervals, what decimal is at the 4th tick after 2?

Answer: 2.4

Each interval is 0.1, so add 4 tenths to 2 to get 2.4.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 20 · representation · 2 points

Write 4 tenths and 3 hundredths as one decimal.

Answer: 0.43

4 tenths is 40 hundredths, plus 3 more makes 43 hundredths.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 21 · representation · 2 points

Write 86/100 as a two-decimal-place number.

100-square whole
Answer: 0.86

86 hundredths are 0.86.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 22 · representation · 2 points

Write 1/10 as a decimal and explain its tenths digit.

One whole split into ten tenths
Answer: 0.1

1 equal tenths of the same whole are written 0.1.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 23 · reasoning · 3 points

Write 0.93 as a fraction in simplest form. Explain how place value or a model can check your result.

Answer: 93/100

0.93 = 93/100. Reduce by the common factor 1 to 93/100. A correct explanation should name the relevant fractional place values and verify the answer.

Scoring (3 points): 1 point for identifying the relevant property; 1 for a correct solution; 1 for reasoning.

Question 24 · reasoning · 3 points

Round 9.31 to the nearest tenth. Explain how place value or a model can check your result.

Answer: 9.3

Use the two neighboring nearest tenth benchmarks, identify their midpoint, and round the original number 9.31 directly. A correct explanation should name the relevant fractional place values and verify the answer.

Scoring (3 points): 1 point for identifying the relevant property; 1 for a correct solution; 1 for reasoning.

Question 25 · decimal · 2 points

Write 5/20 as a decimal.

Answer: 0.25

Rename 5/20 in tenths or hundredths (or divide numerator by denominator) to get 0.25.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 26 · number bond · 2 points

How many tenths must be added to 0.9 to make one whole?

Answer: 1 tenths

One whole is 10 tenths. Subtract 9 from 10 to find the missing parts.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 27 · reasoning · 3 points

Write 22/100 as a two-decimal-place number. Explain how place value or a model can check your result.

100-square whole
Answer: 0.22

22 hundredths are 0.22. A correct explanation should name the relevant fractional place values and verify the answer.

Scoring (3 points): 1 point for identifying the relevant property; 1 for a correct solution; 1 for reasoning.

Question 28 · equivalent decimal · 2 points

How many hundredths are in 7 tenths?

Answer: 70 hundredths

Each tenth consists of 10 hundredths; 7×10=70.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 29 · fraction · 2 points

Write 0.55 as a fraction in simplest form.

Answer: 11/20

0.55 = 55/100. Reduce by the common factor 5 to 11/20.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 30 · numberline · 2 points

On a number line from 2 to 3 divided into ten equal intervals, what decimal is at the 3rd tick after 2?

Answer: 2.3

Each interval is 0.1, so add 3 tenths to 2 to get 2.3.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 31 · reasoning · 3 points

Explain why the decimal 0.3 is the same quantity as 3 tenths.

Answer: They both represent 3 of ten equal parts

A decimal tenths digit counts the same equal parts as numerator 3 over denominator 10.

Scoring (3 points): 1 point for identifying the relationship; 1 point for the correct working or figure; 1 point for a justified answer.

Question 32 · reasoning · 3 points

Write 6/25 as a decimal. Explain how place value or a model can check your result.

Answer: 0.24

Rename 6/25 in tenths or hundredths (or divide numerator by denominator) to get 0.24. A correct explanation should name the relevant fractional place values and verify the answer.

Scoring (3 points): 1 point for identifying the relevant property; 1 for a correct solution; 1 for reasoning.

Question 33 · fraction · 2 points

Write 0.51 as a fraction in simplest form.

Answer: 51/100

0.51 = 51/100. Reduce by the common factor 1 to 51/100.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 34 · numberline · 2 points

On a number line from 5 to 6 divided into ten equal intervals, what decimal is at the 5th tick after 5?

Answer: 5.5

Each interval is 0.1, so add 5 tenths to 5 to get 5.5.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 35 · fraction · 2 points

Write 0.95 as a fraction in simplest form.

Answer: 19/20

0.95 = 95/100. Reduce by the common factor 5 to 19/20.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 36 · rounding · 2 points

Round 6.56 to the nearest tenth.

Answer: 6.6

Use the two neighboring nearest tenth benchmarks, identify their midpoint, and round the original number 6.56 directly.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 37 · rounding · 2 points

Round 8.97 to the nearest whole number.

Answer: 9

Use the two neighboring nearest whole number benchmarks, identify their midpoint, and round the original number 8.97 directly.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 38 · reasoning · 3 points

Order 0.98, 0.57, and 0.09 from least to greatest. Explain how place value or a model can check your result.

Answer: 0.09, 0.57, 0.98

Convert all to hundredths and sort the integer counts. A correct explanation should name the relevant fractional place values and verify the answer.

Scoring (3 points): 1 point for identifying the relevant property; 1 for a correct solution; 1 for reasoning.

Question 39 · representation · 2 points

Write 9/10 as a decimal and explain its tenths digit.

One whole split into ten tenths
Answer: 0.9

9 equal tenths of the same whole are written 0.9.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.

Question 40 · equivalent decimal · 2 points

How many hundredths are in 1 tenth?

Answer: 10 hundredths

Each tenth consists of 10 hundredths; 1×10=10.

Scoring (2 points): 1 point for a sound method and 1 point for a correct, labeled answer.