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Math Main Page => Exercises - Math III
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Goal: to practise 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 March 13 2010
10:43:22 PM | Saturday March 13 2010
10:43:22 PMFlip Answers |
| 1) | 199 * 201 = | | 1) 200 * 200 - 1 * 1 = 39999 |
| 2) | 94 * 106 = | | 2) 100 * 100 - 6 * 6 = 9964 |
| 3) | 290 * 310 = | | 3) 300 * 300 - 10 * 10 = 89900 |
| 4) | 309 * 291 = | | 4) 300 * 300 - 9 * 9 = 89919 |
| 5) | 197 * 203 = | | 5) 200 * 200 - 3 * 3 = 39991 |
| 6) | 294 * 306 = | | 6) 300 * 300 - 6 * 6 = 89964 |
| 7) | 92 * 108 = | | 7) 100 * 100 - 8 * 8 = 9936 |
| 8) | 203 * 197 = | | 8) 200 * 200 - 3 * 3 = 39991 |
| 9) | 296 * 304 = | | 9) 300 * 300 - 4 * 4 = 89984 |
| 10) | 199 * 201 = | | 10) 200 * 200 - 1 * 1 = 39999 |
| 11) | 22 * 151 + 22 * 49 = | | 11) ( 151 + 49) * 22 = 4400 |
| 12) | 75 * 172 - 72 * 75 = | | 12) ( 172 - 72) * 75 = 7500 |
| 13) | 63 * 159 - 59 * 63 = | | 13) ( 159 - 59) * 63 = 6300 |
| 14) | 157 * 77 - 77 * 57 = | | 14) ( 157 - 57) * 77 = 7700 |
| 15) | 272 * 47 - 47 * 72 = | | 15) ( 272 - 72) * 47 = 9400 |
| 16) | 96 * 271 - 71 * 96 = | | 16) ( 271 - 71) * 96 = 19200 |
| 17) | 270 * 66 - 66 * 70 = | | 17) ( 270 - 70) * 66 = 13200 |
| 18) | 36 * 46 + 46 * 64 = | | 18) ( 36 + 64) * 46 = 4600 |
| 19) | 28 * 31 + 28 * 69 = | | 19) ( 31 + 69) * 28 = 2800 |
| 20) | 85 * 161 - 85 * 61 = | | 20) ( 161 - 61) * 85 = 8500 |
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Score: ______________ | |
