Show:
Estimation
Adding and Subtracting Decimals
Multiplying and Dividing Decimals
Adding and Subtracting Integers
Multiplying and Dividing Integers
100

Use front end estimation:

2.47 + 3.4

6

100

Add.

32.78 + 41.2

43.98

100

Divide.

12.76 * 3.2

40.832

100

Add.

18 + 21

39

100

Multiply.

(-8)(9)

-72

200

Round to the nearest whole number.


32.4 - 23. 19

9

200

Subtract.

79.5 - 31.45

48.05

200

Divide.

7.2 / .01

720

200

Subtract.

(-32) + 17

-15

200

Divide.

(-140)/7

-20

300

Use front end estimation:


42.3 + 12.21 + 15.14

70

300

Subtract.

1000 - 32.65

967.35

300

Divide.

54.9 / .03

1,830

300

Subtract.

(-19) - (-14)

-5

300

Multiply.

(-18)(-13)

234

400

Use compatible numbers:


34.2 / 12.3

3

400

Add.

957.8 + 256.74 + 127.432

1,341.972

400

Divide.

132.9 / .3

443

400

Subtract.

(-1,154) - 997

-2,151

400

Divide.

(-1,100)/10

-110

500

Use compatible numbers:

49.78 / 4.75

10

500

Subtract.

542.984 - 239.21 - 13.976

289.798

500

Divide.

.8 / .04

20

500

Subtract.

379 - 572

193

500

Multiply.

(-72)(-84)

6,048