Math Main Page => Exercises - Math III
|
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
|
|
Friday February 03 2012
08:58:14 PM | Friday February 03 2012
08:58:14 PMFlip Answers |
| 1) | 198 * 202 = | | 1) 200 * 200 - 2 * 2 = 39996 |
| 2) | 390 * 410 = | | 2) 400 * 400 - 10 * 10 = 159900 |
| 3) | 191 * 209 = | | 3) 200 * 200 - 9 * 9 = 39919 |
| 4) | 303 * 297 = | | 4) 300 * 300 - 3 * 3 = 89991 |
| 5) | 309 * 291 = | | 5) 300 * 300 - 9 * 9 = 89919 |
| 6) | 393 * 407 = | | 6) 400 * 400 - 7 * 7 = 159951 |
| 7) | 390 * 410 = | | 7) 400 * 400 - 10 * 10 = 159900 |
| 8) | 90 * 110 = | | 8) 100 * 100 - 10 * 10 = 9900 |
| 9) | 403 * 397 = | | 9) 400 * 400 - 3 * 3 = 159991 |
| 10) | 93 * 107 = | | 10) 100 * 100 - 7 * 7 = 9951 |
| 11) | 36 * 34 + 34 * 64 = | | 11) ( 64 + 36) * 34 = 3400 |
| 12) | 21 * 148 - 48 * 21 = | | 12) ( 148 - 48) * 21 = 2100 |
| 13) | 25 * 149 - 49 * 25 = | | 13) ( 149 - 49) * 25 = 2500 |
| 14) | 158 * 34 - 58 * 34 = | | 14) ( 158 - 58) * 34 = 3400 |
| 15) | 81 * 70 + 81 * 130 = | | 15) ( 130 + 70) * 81 = 16200 |
| 16) | 97 * 154 + 46 * 97 = | | 16) ( 154 + 46) * 97 = 19400 |
| 17) | 67 * 158 - 58 * 67 = | | 17) ( 158 - 58) * 67 = 6700 |
| 18) | 257 * 89 - 89 * 57 = | | 18) ( 257 - 57) * 89 = 17800 |
| 19) | 39 * 131 + 39 * 69 = | | 19) ( 131 + 69) * 39 = 7800 |
| 20) | 45 * 253 - 53 * 45 = | | 20) ( 253 - 53) * 45 = 9000 |
|
Score: ______________ | |
