Thursday, February 17, 2011

Compliments of 10 10をつくるには

Knowing the compliments of 10 is crucial for my students to move on to the next stage of arithmetic.  If they can group numbers that equal 10 first, then they have easier time adding and subtracting numbers mentally.

For example, if they know 1+9 and 2+8 are both 10, when they do 382+18, it would be easier and faster for them to answer.

Therefore, I sat for awhile to come up with some manipulative tools for them to work with, so that they can visually and kinesthetically see the relationship between numbers.  I wanted them to be able to "see" them!

I had each student make these 12 sets of little boxes which they colored in (and I laminated).

----------------------------- (Japanese -------------------------------





When you put the correct pair of number on the partner (compliment) number, it will create a complete boxes of 10 (as shown below) like a puzzle!


Here are some interactive on-line games.

Well, I will have them practice with this until they can automatically think of "2" when I show them "8."

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