Sample1
(1) Calculate, paying attention to the parentheses
| (45 + 4) + 8 = | (62 + 7) + 6 = | (90 + 8) + 9 = | 5 + (71 + 7) = |
| 9 + (35 + 14) = | 10 + (52 + 10) = | (32 + 16) + 7 = | 7 + (40 + 6) = |
(2) Calculate:
| 48 + = 65 | + 59 = 93 | 62 − = 25 | − 30 = 63 |
| 26 + = 84 | + 54 = 80 | 97 − = 40 | − 65 = 29 |
| 58 + = 92 | + 70 = 97 | 75 − = 35 | − 68 = 36 |
(3) Subtract and check by adding
| 80 − 30 = 50 | since 50 + 30 = 80 | 76 − 30 = | since + 30 = |
| 85 − 20 = | since + 20 = | 90 − 30 = | since + 30 = |
| 55 − 20 = | since + 20 = | 47 − 30 = | since + 30 = |
| 71 − 20 = | since + 20 = | 72 − 30 = | since + 30 = |
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