Adjusting to Subtract
Estimating Differences
100

Adjust the numbers.

53 - 38 = _____

53 - 38 = 15

100

Estimate the difference.

62 - 38 ≈ _____

62 - 38 ≈ 60 - 40 ≈ 20

200

Adjust the numbers.

65 - 23 = _____

65 - 23 = 42

200

Estimate the difference.

78 - 43 ≈ _____

78 - 43 ≈ 80 - 40 ≈ 40

300

Adjust the numbers.

83 - 41 = _____

83 - 41 = 42

300

Estimate the difference.

46 - 19 ≈ _____

46 - 19 ≈ 50 - 20 ≈ 30

400

Adjust the numbers.

66 - 18 = _____

66 - 18 = 48

400

Estimate the difference.

68 - 23 ≈ _____

68 - 23 ≈ 70 - 20 ≈ 50

500

Tabitha and Johnny have rock collections. Tabitha has 67 rocks and Johnny has 29.  How many more rocks does Tabitha have? Adjust the numbers to solve. 

38 rocks

500

There were 62 butterflies in the air. 26 of them flew away. About how many butterflies were left? Estimate your answer.

≈ 30 butterflies

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