I need something explained from the Singapore 1A HIG.

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Can I put on my best valley girl accent and say "I don't get it!"?

We're doing Unit 6, subtracting from a 2 digit number by subtracting from a 10. Pg. 74 of the HIG.

They ask you to write some problems in the following format, and ask your student to fill in the blanks:

13-6=______ +3

14-7=3+________

I can fill in the blanks and figure out what the number should be. I don't see the point or what I'm supposed to be explaining. Then, on the mental math, they have problems like:

12-10=0+______

Those are on Mental math 17, pg. a7.

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Explain like this:

13-6=______ +3

is the same as ( 10 +3 ) -6. First you subtract the 6 from the 10 and add it to the 3.

14-7=3+________

is the same as (10 + 4) -7. First you subtract the 7 from the 10 and obtain 3. Add the 3 to the 4.

Does this help?

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I look at it as a strategy (one of many). Sometimes the strategy works out, sometimes another strategy works better.

That's what I like about the program we are using now. It says: solve by any convenient method.

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That does make sense, thank you both.

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