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 March 11 2026
06:21:25 PM | Wednesday March 11 2026
06:21:25 PMFlip Answers |
| 1) | 309 * 291 = | | 1) 300 * 300 - 9 * 9 = 89919 |
| 2) | 390 * 410 = | | 2) 400 * 400 - 10 * 10 = 159900 |
| 3) | 109 * 91 = | | 3) 100 * 100 - 9 * 9 = 9919 |
| 4) | 401 * 399 = | | 4) 400 * 400 - 1 * 1 = 159999 |
| 5) | 108 * 92 = | | 5) 100 * 100 - 8 * 8 = 9936 |
| 6) | 303 * 297 = | | 6) 300 * 300 - 3 * 3 = 89991 |
| 7) | 310 * 290 = | | 7) 300 * 300 - 10 * 10 = 89900 |
| 8) | 196 * 204 = | | 8) 200 * 200 - 4 * 4 = 39984 |
| 9) | 409 * 391 = | | 9) 400 * 400 - 9 * 9 = 159919 |
| 10) | 405 * 395 = | | 10) 400 * 400 - 5 * 5 = 159975 |
| 11) | 72 * 58 + 58 * 128 = | | 11) ( 128 + 72) * 58 = 11600 |
| 12) | 82 * 140 + 60 * 82 = | | 12) ( 140 + 60) * 82 = 16400 |
| 13) | 78 * 130 + 78 * 70 = | | 13) ( 130 + 70) * 78 = 15600 |
| 14) | 60 * 40 + 60 * 160 = | | 14) ( 160 + 40) * 60 = 12000 |
| 15) | 54 * 253 - 53 * 54 = | | 15) ( 253 - 53) * 54 = 10800 |
| 16) | 43 * 77 + 77 * 57 = | | 16) ( 57 + 43) * 77 = 7700 |
| 17) | 74 * 69 + 131 * 74 = | | 17) ( 131 + 69) * 74 = 14800 |
| 18) | 48 * 54 + 54 * 52 = | | 18) ( 52 + 48) * 54 = 5400 |
| 19) | 54 * 169 - 54 * 69 = | | 19) ( 169 - 69) * 54 = 5400 |
| 20) | 153 * 66 - 53 * 66 = | | 20) ( 153 - 53) * 66 = 6600 |
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Score: ______________ | |
