Estimate Decimal Sums and Differences

The lengths for four horseback riding trails is shown below. Estimate the total length of all the trails by rounding to the nearest whole number.

Trail A = 2.6 miles

Trail B = 1.8 miles

Trail C = 4.2 miles

Trail D = 3.3 miles

Round 5.67 to the nearest whole number for estimation.

• 6

• 8

• 7

• 5

What are compatible numbers?

• Two of the same numbers.

• Numbers that have the same digit in the ones place.

• Pairs of numbers that are easy to add, subtract, multiply, or divide mentally.

• Numbers that have the same amount of digits.

What is the estimated sum of 3.25 and 2.73?

• 5.98

• 4.98

• 5.48

• 6.25

Estimate the difference between 6.84 and 4.29.

• 2.55

• 3.75

• 5.92

• 1.23

Estimate the difference between 9.73 and 3.89.

• 5.84

• 4.84

• 2.84

• 7.84

Calculate the sum of 2.34 and 6.78.

• 9.12

• 8.12

• 5.56

• 10.34

Find the difference between 9.67 and 3.45.

• 6.22

• 2.33

• 7.89

• 5.12

Subtract 7.23 from 9.87.

• 16.1

• 5.23

• 2.64

• 3.64

Round 7.42 to the nearest whole number for estimation.

• 7.5

• 6

• 7

• 8