1 A
2 C
3 B
4 C
5 D
6 B
7 A
8 D
9 A
10 C
11 B
12 70 UNDERESTIMATE
13 60 OVERESTIMATE
14 40 + 23 = 63
15 21 + 50 = 71
16 15 , 7 , 8 , 7
17 10 , 6 , 6 , 4
18 3 + 6 = 9
6 +3 = 9
9 _ 3 = 6
9 _ 6 = 3
19 94 _ 20 = 74
20 34 _10 = 24
21 12
22 67 _ 40 = 27
23 200 _ 100 = 100
24 500 _ 100 = 400
25 10 + 50 = 60
26 30 + 170 = 200