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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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Friday November 20 2009
06:55:37 PM | Friday November 20 2009
06:55:37 PMFlip Answers |
| 1) | 92 * 108 = | | 1) 100 * 100 - 8 * 8 = 9936 |
| 2) | 190 * 210 = | | 2) 200 * 200 - 10 * 10 = 39900 |
| 3) | 209 * 191 = | | 3) 200 * 200 - 9 * 9 = 39919 |
| 4) | 308 * 292 = | | 4) 300 * 300 - 8 * 8 = 89936 |
| 5) | 399 * 401 = | | 5) 400 * 400 - 1 * 1 = 159999 |
| 6) | 305 * 295 = | | 6) 300 * 300 - 5 * 5 = 89975 |
| 7) | 97 * 103 = | | 7) 100 * 100 - 3 * 3 = 9991 |
| 8) | 101 * 99 = | | 8) 100 * 100 - 1 * 1 = 9999 |
| 9) | 194 * 206 = | | 9) 200 * 200 - 6 * 6 = 39964 |
| 10) | 208 * 192 = | | 10) 200 * 200 - 8 * 8 = 39936 |
| 11) | 34 * 56 + 66 * 56 = | | 11) ( 34 + 66) * 56 = 5600 |
| 12) | 47 * 243 - 47 * 43 = | | 12) ( 243 - 43) * 47 = 9400 |
| 13) | 265 * 57 - 57 * 65 = | | 13) ( 265 - 65) * 57 = 11400 |
| 14) | 171 * 51 - 71 * 51 = | | 14) ( 171 - 71) * 51 = 5100 |
| 15) | 71 * 164 + 71 * 36 = | | 15) ( 164 + 36) * 71 = 14200 |
| 16) | 143 * 81 - 81 * 43 = | | 16) ( 143 - 43) * 81 = 8100 |
| 17) | 49 * 39 + 49 * 61 = | | 17) ( 61 + 39) * 49 = 4900 |
| 18) | 159 * 63 - 59 * 63 = | | 18) ( 159 - 59) * 63 = 6300 |
| 19) | 51 * 260 - 60 * 51 = | | 19) ( 260 - 60) * 51 = 10200 |
| 20) | 59 * 62 + 62 * 41 = | | 20) ( 59 + 41) * 62 = 6200 |
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Score: ______________ | |
