To multiply two 2-digit numbers without showing work, first multiply the ones digits together, then 'cross-multiply,' and finally multiply the tens digits together. Make sure to carry whenever a product exceeds 9. As you will see in the examples below, you must work your way from right to left to perform this trick. Example 1: 12 x 23
Example 2: 31 x 24
Note: This trick will also work on numbers with zeroes and decimal points. Also as you are cross-multiplying, it is generally easier to begin with the larger product and then add the smaller product. Comments are closed.
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