Rounding
52+27=?
52---50
27---30
50+30=80
10+50+20=?
80
14+13=?
27
10 more than 50
60
42+15=?
57
12+12=?
12---10
12---10
10+10=20
Doubles fact
124+230=?
354
57+38=?
95
100 more than 30
130
65+25=?
90
159+31=?
159---200
31---30
200+30=230
10+35+40+11=?
96
118+111=?
229
100 more than 200
300
29+10+19=?
58
504+19=?
504---500
19---20
500+20=520
159+212=?
371
168+392=?
560
10 more than 68
78
131+224=?
355
468+457=?
468---500
457---500
500+500=1,000
134+29+256+12=?
431
15+29+49=?
93
100 more 379
479
250+12+379=?
641