Estimation sums up to 100
Use rounding to estimate the answer to the addition problem.
Check
51 + 29
???
100
70
80
90
40
50
22 + 77
???
100
70
80
90
40
50
47 + 39
???
100
70
80
90
40
50
28 + 39
???
100
70
80
90
40
50
28 + 18
???
100
70
80
90
40
50
24 + 18
???
100
70
80
90
40
50
41 + 58
???
100
70
80
90
40
50
77 + 9
???
100
70
80
90
40
50
64 + 19
???
100
70
80
90
40
50
66 + 19
???
100
70
80
90
40
50
Check
OK