Fast Mental Multiplication Trick - Multiply in your head using base 20 and 30

This mental multiplication trick uses the idea of a third number - a base number - to help us multiply two numbers in your head. This series of videos first looks at multiplying numbers near 10 using base 10. The second video looks at multiplying using base 20 and 30. The third video looks at how to apply this mental multiplication trick to numbers near 50. The forth video the investigates ho to easilt mentally multiply numbers near to 100. Continue your mental math multiplication abilties here!

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