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 January 02 2026
06:55:49 AM | Friday January 02 2026
06:55:49 AMFlip Answers |
| 1) | 109 * 91 = | | 1) 100 * 100 - 9 * 9 = 9919 |
| 2) | 409 * 391 = | | 2) 400 * 400 - 9 * 9 = 159919 |
| 3) | 401 * 399 = | | 3) 400 * 400 - 1 * 1 = 159999 |
| 4) | 398 * 402 = | | 4) 400 * 400 - 2 * 2 = 159996 |
| 5) | 305 * 295 = | | 5) 300 * 300 - 5 * 5 = 89975 |
| 6) | 204 * 196 = | | 6) 200 * 200 - 4 * 4 = 39984 |
| 7) | 299 * 301 = | | 7) 300 * 300 - 1 * 1 = 89999 |
| 8) | 93 * 107 = | | 8) 100 * 100 - 7 * 7 = 9951 |
| 9) | 210 * 190 = | | 9) 200 * 200 - 10 * 10 = 39900 |
| 10) | 310 * 290 = | | 10) 300 * 300 - 10 * 10 = 89900 |
| 11) | 136 * 54 + 64 * 54 = | | 11) ( 136 + 64) * 54 = 10800 |
| 12) | 45 * 55 + 145 * 45 = | | 12) ( 145 + 55) * 45 = 9000 |
| 13) | 138 * 21 + 21 * 62 = | | 13) ( 138 + 62) * 21 = 4200 |
| 14) | 264 * 47 - 64 * 47 = | | 14) ( 264 - 64) * 47 = 9400 |
| 15) | 86 * 235 - 35 * 86 = | | 15) ( 235 - 35) * 86 = 17200 |
| 16) | 97 * 57 + 97 * 143 = | | 16) ( 143 + 57) * 97 = 19400 |
| 17) | 235 * 23 - 35 * 23 = | | 17) ( 235 - 35) * 23 = 4600 |
| 18) | 79 * 51 + 79 * 49 = | | 18) ( 49 + 51) * 79 = 7900 |
| 19) | 267 * 71 - 71 * 67 = | | 19) ( 267 - 67) * 71 = 14200 |
| 20) | 47 * 235 - 47 * 35 = | | 20) ( 235 - 35) * 47 = 9400 |
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Score: ______________ | |
