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In this worksheet, students estimate additions by rounding both decimals to the nearest whole numbers before adding them.

Key stage:  KS 2

Curriculum topic:   Maths and Numerical Reasoning

Curriculum subtopic:   Decimals

Difficulty level:

### QUESTION 1 of 10

We can estimate answers to complicated additions by rounding both decimals to the nearest whole numbers before adding them together.

Example:

64.51 + 18.15 can be estimated by working out 65 + 18

= 83

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

57.8 + 79.86  =   ____  +  ____  =   ____

 Rounded Numbers 57.8 79.86 Sum

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

96.77 + 79.18  =   ____  +  ____  =   ____

 Rounded Numbers 96.77 79.18 Sum

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

88.54 + 25.59  =   ____  +  ____  =   ____

 Rounded Numbers 88.54 25.59 Sum

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

85.21 + 98.56  =   ____  +  ____  =   ____

 Rounded Numbers 85.21 98.56 Sum

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

36.53 + 11.53  =   ____  +  ____  =   ____

 Rounded Numbers 36.53 11.53 Sum

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

48.06 + 33.82   =   ____  +  ____  =   ____

 Rounded Numbers 48.06 33.82 Sum

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

29.78 + 51.55  =   ____  +  ____  =   ____

 Rounded Numbers 29.78 51.55 Sum

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

30.42 + 20.6  =   ____  +  ____  =   ____

 Rounded Numbers 30.42 20.6 Sum

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

42.44 + 16.42  =   ____  +  ____  =   ____

 Rounded Numbers 42.44 16.42 Sum

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum.

38.72 + 16.74 =   ____  +  ____  =   ____

 Rounded Numbers 38.72 16.74 Sum
• Question 1

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

57.8 + 79.86  =   ____  +  ____  =   ____

 Rounded Numbers 57.8 79.86 Sum
EDDIE SAYS
57.8 rounds up to 58, 79.86 rounds up to 80, and 58 + 80 = 138
• Question 2

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

96.77 + 79.18  =   ____  +  ____  =   ____

 Rounded Numbers 96.77 79.18 Sum
EDDIE SAYS
96.77 rounds up to 97, 79.18 rounds down to 79, and 97 + 79 = 176.
• Question 3

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

88.54 + 25.59  =   ____  +  ____  =   ____

 Rounded Numbers 88.54 25.59 Sum
EDDIE SAYS
88.54 rounds up to 89, 25.59 rounds up to 26 and 89 + 26 = 115.
• Question 4

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

85.21 + 98.56  =   ____  +  ____  =   ____

 Rounded Numbers 85.21 98.56 Sum
EDDIE SAYS
85.21 rounds down to 85, 98.56 rounds up to 99, and 85 + 99 = 184.
• Question 5

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

36.53 + 11.53  =   ____  +  ____  =   ____

 Rounded Numbers 36.53 11.53 Sum
EDDIE SAYS
36.53 rounds up to 37, 11.53 rounds up to 12, and 17 + 12 = 49
• Question 6

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

48.06 + 33.82   =   ____  +  ____  =   ____

 Rounded Numbers 48.06 33.82 Sum
EDDIE SAYS
48.06 rounds down to 48, 33.82 rounds up to 34, and 48 + 34 = 82
• Question 7

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

29.78 + 51.55  =   ____  +  ____  =   ____

 Rounded Numbers 29.78 51.55 Sum
EDDIE SAYS
29.78 rounds up to 30, 51.55 rounds up to 52, and 30 + 52 = 82.
• Question 8

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

30.42 + 20.6  =   ____  +  ____  =   ____

 Rounded Numbers 30.42 20.6 Sum
EDDIE SAYS
30.42 rounds down to 30, 20.6 rounds up to 21, and 30 + 21 = 51.
• Question 9

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum. Write the rounded numbers and the sum in the boxes below.

42.44 + 16.42  =   ____  +  ____  =   ____

 Rounded Numbers 42.44 16.42 Sum
EDDIE SAYS
42.44 rounds down to 42, 16.42 rounds down to 16, and 42 + 16 = 58.
• Question 10

Estimate the answers to this addition by rounding the numbers to the nearest whole numbers before finding the sum.

38.72 + 16.74 =   ____  +  ____  =   ____

 Rounded Numbers 38.72 16.74 Sum
EDDIE SAYS
38.72 rounds up to 39, 16.74 rounds up to 17, and 39 + 17 = 56.
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