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 August 14 2026
02:44:20 PM | Friday August 14 2026
02:44:20 PMFlip Answers |
| 1) | 101 * 99 = | | 1) 100 * 100 - 1 * 1 = 9999 |
| 2) | 90 * 110 = | | 2) 100 * 100 - 10 * 10 = 9900 |
| 3) | 410 * 390 = | | 3) 400 * 400 - 10 * 10 = 159900 |
| 4) | 392 * 408 = | | 4) 400 * 400 - 8 * 8 = 159936 |
| 5) | 306 * 294 = | | 5) 300 * 300 - 6 * 6 = 89964 |
| 6) | 102 * 98 = | | 6) 100 * 100 - 2 * 2 = 9996 |
| 7) | 398 * 402 = | | 7) 400 * 400 - 2 * 2 = 159996 |
| 8) | 303 * 297 = | | 8) 300 * 300 - 3 * 3 = 89991 |
| 9) | 108 * 92 = | | 9) 100 * 100 - 8 * 8 = 9936 |
| 10) | 96 * 104 = | | 10) 100 * 100 - 4 * 4 = 9984 |
| 11) | 155 * 80 + 80 * 45 = | | 11) ( 155 + 45) * 80 = 16000 |
| 12) | 21 * 165 + 21 * 35 = | | 12) ( 165 + 35) * 21 = 4200 |
| 13) | 144 * 61 - 44 * 61 = | | 13) ( 144 - 44) * 61 = 6100 |
| 14) | 65 * 85 + 85 * 135 = | | 14) ( 135 + 65) * 85 = 17000 |
| 15) | 168 * 90 - 68 * 90 = | | 15) ( 168 - 68) * 90 = 9000 |
| 16) | 245 * 56 - 56 * 45 = | | 16) ( 245 - 45) * 56 = 11200 |
| 17) | 86 * 48 + 86 * 52 = | | 17) ( 48 + 52) * 86 = 8600 |
| 18) | 245 * 54 - 45 * 54 = | | 18) ( 245 - 45) * 54 = 10800 |
| 19) | 55 * 48 + 48 * 45 = | | 19) ( 55 + 45) * 48 = 4800 |
| 20) | 81 * 141 + 59 * 81 = | | 20) ( 141 + 59) * 81 = 16200 |
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Score: ______________ | |
