Addition
Subtraction
Multiplication
Division
Random
100
Front-end Addition: 378+211=?
589
100
Front-end Subtraction: 57-31=?
26
100
Front-end Multiplication: 3,010 x 2=?
6,020
100
Front-end Division: 9633/3=?
3211
100
Multiply/Divide by 10, 100, 1,000: 4.5 x 100
450
200
Compatible Numbers for Addition: 25+7+8+12+25=?
77
200
Compatible Numbers for Subtraction: 16-6+32-12=?
30
200
Compatible Numbers for Multiplication: 2 x 8 x 5 x 7=?
560
200
Divide by 5 by Doubling and then Dividing by 10: 24/5=?
4.8
200
Solve Proportions by Doubling of Halving: y/7=30/21
10
300
Break Apart: (12 x 6) + 5=?
77
300
Drop the Zeros, Subtract, Then Put Them Back On: 5,200-300=?
4,900
300
Double Any Number up to 50: 36 x 2=?
72
300
Cancel Zeros, Drop Some of the Zeros, Divide, Then “Put Them Back On”: 300,000/50=?
6,000
300
Multiply by a Unit Fraction by Dividing: 1/4 x 20=?
5
400
Compensation: 65+38=?
103
400
Substitute Compatible Numbers: 38+300+65=?
403
400
Multiply by 11 or 12: 12 x 6=?
72
400
Divide by 4 by Dividing by 2 Twice: 88/4
22
400
Multiply Decimals by Dropping the Decimal and Putting it Back in Later: .8 x .2
.16
500
Front-end Estimation with Adjustment: 859+221+112+523=?
1600
500
Part-Part-Whole on 100: 200-41=?
159
500
Multiply by 4 by Doubling Twice: 35 x 4=?
140
500
Halve Any Even Number less than or equal to 100: 54/2=?
27
500
Solve Proportions using Factor of Change: 3/8=y/24
9
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