Estimating Addends to Find the Sum

Find the Missing Addend: 3 + ___ = 15

• 18

• 15

• 12

• 9

Find the Missing Addend

12 + ___ = 19

• 7

• 31

• 5

• 21

Find the Missing Addend

6 + ___ = 15

Find the Missing Addend 5 + ___ = 16

• 11

• 12

• 10

• 13

Use mental math to solve.

120 + 42 + 80

Evaluate responses using AI:

OFF

A way of estimating that uses the first digit in each number in a calculation.

• rounding

• guessing

• front-end estimation

• evaluate

An approximate answer; to find an answer that is close to the exact answer.

• sum

• difference

• estimate

• guess

Estimate using addition and subtraction. Round to the

nearest dollar before estimating. Remember to write the problem vertically.

$11.33 +32.43 =

Estimate using addition and subtraction. Round to the nearest ten before estimating. Remember to write the problem vertically before estimating. 79 + 42 =

Estimate using addition and subtraction. Round to the

nearest whole number before estimating.

8.1 + 3.7 + 7.9