Mental Math
Compensation Addition
Count on
Standard Algorithm Addition
Standard Algorithm Subtraction
100
41
29+12
100
88
48+40
100
165
200-35
100
1131
789+342
100
23
100-77
200
102
78+24
200
205
95+110
200
290
500-210
200
2,295
1,839+456
200
277
400-123
300
132
97+35
300
114
33+81
300
450
700-250
300
5,273
3,928+1,345
300
311
1,000-689
400
550
595+55
400
445
195+250
400
655
1000-445
400
9,454
5,899+3,555
400
8,211
12,000-3,789
500
1,200
982+218
500
895
785+110
500
2,210
3,000-790
500
17,443
11,888+5,555
500
65,433
100,000-34,567
M
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