Tuesday, July 31, 2007
MATH TRICKS
Staying true to the Chinese stereotype, my dad is very good at math. And he used to make sure he imparted his mathematical skills onto his kids, often by teaching us tricks or shortcuts to help get the job done faster.
Two of my favorites are:
(1) Thinking about multiplication of 25 like you're using quarters. For example, I always had to manually do the math for something like 25 x 9. But when I thought about it like 9 quarters, $2.25 just came naturally. Bam! 25x9 = 225
(2) When you multiplying the same number that ends in 5 (like 35 x 35 or 65 x 65), you can just add 1 to the first number and multiply those numbers and add 25 at the end to get the answer. For example, 35x35. Take 3 and add 1 to get 4. 4x3 = 12. Now add 25 to it and you get the answer: 1225. Or 65x65. Take 6 and add 1 to get 7. 7x6 = 42. Now add 25 to the end and you get 4225.
But yesterday, my dad sent me a 5 minute video of a new trick for multiplying any two numbers between 10 and 19 together. The video is both educational and hilarious because the guy has a very strong Indian accent. Check it out!
Staying true to the Chinese stereotype, my dad is very good at math. And he used to make sure he imparted his mathematical skills onto his kids, often by teaching us tricks or shortcuts to help get the job done faster.
Two of my favorites are:
(1) Thinking about multiplication of 25 like you're using quarters. For example, I always had to manually do the math for something like 25 x 9. But when I thought about it like 9 quarters, $2.25 just came naturally. Bam! 25x9 = 225
(2) When you multiplying the same number that ends in 5 (like 35 x 35 or 65 x 65), you can just add 1 to the first number and multiply those numbers and add 25 at the end to get the answer. For example, 35x35. Take 3 and add 1 to get 4. 4x3 = 12. Now add 25 to it and you get the answer: 1225. Or 65x65. Take 6 and add 1 to get 7. 7x6 = 42. Now add 25 to the end and you get 4225.
But yesterday, my dad sent me a 5 minute video of a new trick for multiplying any two numbers between 10 and 19 together. The video is both educational and hilarious because the guy has a very strong Indian accent. Check it out!
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