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Short Cut for 27 x 26 |
| 1. | This formula is useful with problems that contain the numbers twenty-one through twenty-nine. | 27 | ||
| X 26 | ||||
| ------------ | ||||
| 2. | Add the first
number, twenty-seven, and the ones digit of the second number, six, together or add the
second number, twenty-six, and the ones digit of the first number, seven, together. Then
multiply by the tens digit of the second number, two (the number of tens) for a result of
sixty-six. Place the result, sixty-six, in the hundreds and tens places respectively, as
shown.
|
27 | ||
| X 26 | ||||
| ------------ | ||||
| 66 ................ ( 27 + 6 ) X 2 | ||||
| or ( 7 + 26 ) X 2 | ||||
| 3. | Multiply the numbers
in the ones place of each number, the seven and the six, for a result of forty-two. Place
the result below the result in step 2, sixty-six, in the tens and ones places
respectively, as shown.
|
27 | ||
| X 26 | ||||
| ------------ | ||||
| 66 | ||||
| 42 .................. 7 X 6 | ||||
| 4. | Add the sixty-six and
forty-two together as aligned for a result of 702. |
27 | ||
| X 26 | ||||
| ------------ | ||||
| 66 | ||||
| 42 | ||||
| ------------ | ||||
| 702 | ||||
| 5. | If desired, check using conventional multiplication | |||
| For practice problems using this short cut, click here to go to SumPlus, and set the limits for A and B to be a maximum of 29 and a minimum of 21. Ask for 10 problems per page or it will take few minutes to create problems.. | ||||
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©1994, 2000 Kaidy Educational Resources |
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Limited reproduction for classroom use. |
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