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
|
|
Tuesday November 18 2025
04:59:29 PM | Tuesday November 18 2025
04:59:29 PMFlip Answers |
| 1) | 409 * 391 = | | 1) 400 * 400 - 9 * 9 = 159919 |
| 2) | 301 * 299 = | | 2) 300 * 300 - 1 * 1 = 89999 |
| 3) | 199 * 201 = | | 3) 200 * 200 - 1 * 1 = 39999 |
| 4) | 391 * 409 = | | 4) 400 * 400 - 9 * 9 = 159919 |
| 5) | 202 * 198 = | | 5) 200 * 200 - 2 * 2 = 39996 |
| 6) | 203 * 197 = | | 6) 200 * 200 - 3 * 3 = 39991 |
| 7) | 393 * 407 = | | 7) 400 * 400 - 7 * 7 = 159951 |
| 8) | 198 * 202 = | | 8) 200 * 200 - 2 * 2 = 39996 |
| 9) | 104 * 96 = | | 9) 100 * 100 - 4 * 4 = 9984 |
| 10) | 210 * 190 = | | 10) 200 * 200 - 10 * 10 = 39900 |
| 11) | 162 * 75 - 75 * 62 = | | 11) ( 162 - 62) * 75 = 7500 |
| 12) | 45 * 137 - 37 * 45 = | | 12) ( 137 - 37) * 45 = 4500 |
| 13) | 35 * 92 + 65 * 92 = | | 13) ( 65 + 35) * 92 = 9200 |
| 14) | 64 * 90 + 36 * 90 = | | 14) ( 64 + 36) * 90 = 9000 |
| 15) | 143 * 74 - 43 * 74 = | | 15) ( 143 - 43) * 74 = 7400 |
| 16) | 255 * 58 - 58 * 55 = | | 16) ( 255 - 55) * 58 = 11600 |
| 17) | 67 * 71 + 129 * 67 = | | 17) ( 129 + 71) * 67 = 13400 |
| 18) | 71 * 43 + 129 * 43 = | | 18) ( 129 + 71) * 43 = 8600 |
| 19) | 40 * 23 + 60 * 23 = | | 19) ( 40 + 60) * 23 = 2300 |
| 20) | 61 * 38 + 38 * 139 = | | 20) ( 139 + 61) * 38 = 7600 |
|
Score: ______________ | |
