Estimation
Use front end estimation:
2.47 + 3.4
6
Add.
32.78 + 41.2
43.98
Divide.
12.76 * 3.2
40.832
Add.
18 + 21
39
Multiply.
(-8)(9)
-72
Round to the nearest whole number.
32.4 - 23. 19
9
Subtract.
79.5 - 31.45
48.05
Divide.
7.2 / .01
720
Subtract.
(-32) + 17
-15
Divide.
(-140)/7
-20
Use front end estimation:
42.3 + 12.21 + 15.14
70
Subtract.
1000 - 32.65
967.35
Divide.
54.9 / .03
1,830
Subtract.
(-19) - (-14)
-5
Multiply.
(-18)(-13)
234
Use compatible numbers:
34.2 / 12.3
3
Add.
957.8 + 256.74 + 127.432
1,341.972
Divide.
132.9 / .3
443
Subtract.
(-1,154) - 997
-2,151
Divide.
(-1,100)/10
-110
Use compatible numbers:
49.78 / 4.75
10
Subtract.
542.984 - 239.21 - 13.976
289.798
Divide.
.8 / .04
20
Subtract.
379 - 572
193
Multiply.
(-72)(-84)
6,048