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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Saturday April 11 2026
11:40:18 PM | Saturday April 11 2026
11:40:18 PMFlip Answers |
| 1) | 390 * 410 = | | 1) 400 * 400 - 10 * 10 = 159900 |
| 2) | 305 * 295 = | | 2) 300 * 300 - 5 * 5 = 89975 |
| 3) | 405 * 395 = | | 3) 400 * 400 - 5 * 5 = 159975 |
| 4) | 110 * 90 = | | 4) 100 * 100 - 10 * 10 = 9900 |
| 5) | 91 * 109 = | | 5) 100 * 100 - 9 * 9 = 9919 |
| 6) | 205 * 195 = | | 6) 200 * 200 - 5 * 5 = 39975 |
| 7) | 290 * 310 = | | 7) 300 * 300 - 10 * 10 = 89900 |
| 8) | 96 * 104 = | | 8) 100 * 100 - 4 * 4 = 9984 |
| 9) | 394 * 406 = | | 9) 400 * 400 - 6 * 6 = 159964 |
| 10) | 404 * 396 = | | 10) 400 * 400 - 4 * 4 = 159984 |
| 11) | 34 * 54 + 34 * 46 = | | 11) ( 54 + 46) * 34 = 3400 |
| 12) | 151 * 31 - 31 * 51 = | | 12) ( 151 - 51) * 31 = 3100 |
| 13) | 55 * 48 + 52 * 55 = | | 13) ( 52 + 48) * 55 = 5500 |
| 14) | 35 * 68 + 68 * 165 = | | 14) ( 165 + 35) * 68 = 13600 |
| 15) | 271 * 75 - 71 * 75 = | | 15) ( 271 - 71) * 75 = 15000 |
| 16) | 93 * 45 + 93 * 155 = | | 16) ( 155 + 45) * 93 = 18600 |
| 17) | 92 * 268 - 68 * 92 = | | 17) ( 268 - 68) * 92 = 18400 |
| 18) | 268 * 83 - 83 * 68 = | | 18) ( 268 - 68) * 83 = 16600 |
| 19) | 94 * 44 + 94 * 56 = | | 19) ( 44 + 56) * 94 = 9400 |
| 20) | 130 * 76 + 76 * 70 = | | 20) ( 130 + 70) * 76 = 15200 |
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Score: ______________ | |
