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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Sunday July 26 2026
06:04:52 AM | Sunday July 26 2026
06:04:52 AMFlip Answers |
| 1) | 410 * 390 = | | 1) 400 * 400 - 10 * 10 = 159900 |
| 2) | 99 * 101 = | | 2) 100 * 100 - 1 * 1 = 9999 |
| 3) | 290 * 310 = | | 3) 300 * 300 - 10 * 10 = 89900 |
| 4) | 205 * 195 = | | 4) 200 * 200 - 5 * 5 = 39975 |
| 5) | 290 * 310 = | | 5) 300 * 300 - 10 * 10 = 89900 |
| 6) | 402 * 398 = | | 6) 400 * 400 - 2 * 2 = 159996 |
| 7) | 403 * 397 = | | 7) 400 * 400 - 3 * 3 = 159991 |
| 8) | 310 * 290 = | | 8) 300 * 300 - 10 * 10 = 89900 |
| 9) | 293 * 307 = | | 9) 300 * 300 - 7 * 7 = 89951 |
| 10) | 302 * 298 = | | 10) 300 * 300 - 2 * 2 = 89996 |
| 11) | 42 * 65 + 42 * 135 = | | 11) ( 135 + 65) * 42 = 8400 |
| 12) | 53 * 175 - 53 * 75 = | | 12) ( 175 - 75) * 53 = 5300 |
| 13) | 246 * 90 - 46 * 90 = | | 13) ( 246 - 46) * 90 = 18000 |
| 14) | 64 * 91 + 91 * 36 = | | 14) ( 64 + 36) * 91 = 9100 |
| 15) | 46 * 161 - 61 * 46 = | | 15) ( 161 - 61) * 46 = 4600 |
| 16) | 80 * 28 + 72 * 80 = | | 16) ( 28 + 72) * 80 = 8000 |
| 17) | 86 * 162 - 86 * 62 = | | 17) ( 162 - 62) * 86 = 8600 |
| 18) | 154 * 55 + 46 * 55 = | | 18) ( 154 + 46) * 55 = 11000 |
| 19) | 27 * 130 + 27 * 70 = | | 19) ( 130 + 70) * 27 = 5400 |
| 20) | 61 * 95 + 39 * 95 = | | 20) ( 61 + 39) * 95 = 9500 |
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Score: ______________ | |
