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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Wednesday May 20 2026
11:33:41 AM | Wednesday May 20 2026
11:33:41 AMFlip Answers |
| 1) | 390 * 410 = | | 1) 400 * 400 - 10 * 10 = 159900 |
| 2) | 90 * 110 = | | 2) 100 * 100 - 10 * 10 = 9900 |
| 3) | 199 * 201 = | | 3) 200 * 200 - 1 * 1 = 39999 |
| 4) | 93 * 107 = | | 4) 100 * 100 - 7 * 7 = 9951 |
| 5) | 401 * 399 = | | 5) 400 * 400 - 1 * 1 = 159999 |
| 6) | 201 * 199 = | | 6) 200 * 200 - 1 * 1 = 39999 |
| 7) | 195 * 205 = | | 7) 200 * 200 - 5 * 5 = 39975 |
| 8) | 95 * 105 = | | 8) 100 * 100 - 5 * 5 = 9975 |
| 9) | 195 * 205 = | | 9) 200 * 200 - 5 * 5 = 39975 |
| 10) | 92 * 108 = | | 10) 100 * 100 - 8 * 8 = 9936 |
| 11) | 45 * 97 + 155 * 97 = | | 11) ( 155 + 45) * 97 = 19400 |
| 12) | 72 * 140 - 40 * 72 = | | 12) ( 140 - 40) * 72 = 7200 |
| 13) | 243 * 86 - 86 * 43 = | | 13) ( 243 - 43) * 86 = 17200 |
| 14) | 30 * 147 - 30 * 47 = | | 14) ( 147 - 47) * 30 = 3000 |
| 15) | 56 * 61 + 61 * 144 = | | 15) ( 144 + 56) * 61 = 12200 |
| 16) | 43 * 235 - 35 * 43 = | | 16) ( 235 - 35) * 43 = 8600 |
| 17) | 56 * 44 + 144 * 44 = | | 17) ( 144 + 56) * 44 = 8800 |
| 18) | 27 * 75 + 73 * 75 = | | 18) ( 27 + 73) * 75 = 7500 |
| 19) | 136 * 49 + 64 * 49 = | | 19) ( 136 + 64) * 49 = 9800 |
| 20) | 21 * 36 + 21 * 64 = | | 20) ( 36 + 64) * 21 = 2100 |
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Score: ______________ | |
