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Multiplying 2-Digit Numbers FAST

Multiplying 2-Digit Numbers FAST. Bonnie Parret EDMA 616 December 2013. Can you solve this problem in 7 seconds?. 21 X 13 =. Here’s how you do it…. 21 X 13 = 2 3 Multiply the tens place (2x1) to get the first digit. Multiply the ones place (1x3) to get the last digit.

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Multiplying 2-Digit Numbers FAST

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  1. Multiplying 2-Digit Numbers FAST • Bonnie Parret • EDMA 616 • December 2013

  2. Can you solve this problem in 7 seconds? 21 X 13 =

  3. Here’s how you do it… 21 X 13 = 23 • Multiply the tens place (2x1) to get the first digit. • Multiply the ones place (1x3) to get the last digit. • Leave the tens place open…

  4. To get the digit for the tens place… 21 X 13 = 23 2 x 3 + 1x 1 = 6 +1 = 7 • Multiply the tens by the one individually. (Use rainbow arches to find partners.) • Add the sums together to determine the digit in the tens place

  5. Lets try another one… 12 X 23 = 276 3 + 4 = 7

  6. But what happens if there’s a double digit in the answer? 42 X 23 = 886 12 + 6 = 18 = 986

  7. OK, Let’s try a big one… 82 x 51 = 40 _ 2 8 + 10 = 18 = 4182

  8. Fast Math Trick for Multiplication How to multiply 2 digit numbers • Discovered at tecmath on YouTube • http://www.youtube.com/watch?v=PYrgjMubh-c

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