Math Main Page => Exercises - Math III
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Goal: to practice how to make use of distributive property on special numbers, like (A + B) * (A - B) = A*A - B*B, A*C +B*C = (A + B ) *C, A*C - B*C = (A-B) * C
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Friday May 08 2026
04:28:54 AM | Friday May 08 2026
04:28:54 AMFlip Answers |
| 1) | 391 * 409 = | | 1) 400 * 400 - 9 * 9 = 159919 |
| 2) | 93 * 107 = | | 2) 100 * 100 - 7 * 7 = 9951 |
| 3) | 106 * 94 = | | 3) 100 * 100 - 6 * 6 = 9964 |
| 4) | 402 * 398 = | | 4) 400 * 400 - 2 * 2 = 159996 |
| 5) | 404 * 396 = | | 5) 400 * 400 - 4 * 4 = 159984 |
| 6) | 193 * 207 = | | 6) 200 * 200 - 7 * 7 = 39951 |
| 7) | 110 * 90 = | | 7) 100 * 100 - 10 * 10 = 9900 |
| 8) | 106 * 94 = | | 8) 100 * 100 - 6 * 6 = 9964 |
| 9) | 201 * 199 = | | 9) 200 * 200 - 1 * 1 = 39999 |
| 10) | 209 * 191 = | | 10) 200 * 200 - 9 * 9 = 39919 |
| 11) | 149 * 86 - 86 * 49 = | | 11) ( 149 - 49) * 86 = 8600 |
| 12) | 58 * 140 + 60 * 58 = | | 12) ( 140 + 60) * 58 = 11600 |
| 13) | 238 * 73 - 38 * 73 = | | 13) ( 238 - 38) * 73 = 14600 |
| 14) | 145 * 45 - 45 * 45 = | | 14) ( 145 - 45) * 45 = 4500 |
| 15) | 87 * 33 + 87 * 67 = | | 15) ( 33 + 67) * 87 = 8700 |
| 16) | 42 * 27 + 58 * 27 = | | 16) ( 58 + 42) * 27 = 2700 |
| 17) | 55 * 23 + 145 * 23 = | | 17) ( 145 + 55) * 23 = 4600 |
| 18) | 241 * 80 - 80 * 41 = | | 18) ( 241 - 41) * 80 = 16000 |
| 19) | 84 * 239 - 84 * 39 = | | 19) ( 239 - 39) * 84 = 16800 |
| 20) | 42 * 56 + 42 * 44 = | | 20) ( 56 + 44) * 42 = 4200 |
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Score: ______________ | |
