Add to subtract ... huh?

Jul 12, 2015 | East Sparks

10 keeps proving itself to be one of the most powerful ideas in math.  Ask a kid what 10+7 is and, without batting an eyelash, they'll proudly proclaim, "17".

I see so many of our little ones struggle with subtraction.  Especially when they have a minuend over 10.

Adding, though, is one idea that seems to resonate easier with almost every kid.  With this in mind, try using 10 as a "pit stop".  In the example, we leverage their understanding of 10 + a single digit number and couple that with the idea of complements of 10.  We'd ask:

"How far apart are 4 and 10?" or "How many do we need to add to 4 to make 10?"

Once they understand that they need 6, we're at the pit stop.  The rest of the way is just 10 + a single digit number or 10 + 7.

Part 1 is 6 and part 2 is 7 or 13.

Did we "trick" them into adding instead of subtracting?

All I know is that they'll be able to repeat this over and over and never be wrong and they'll always be confident.  That's ok in my book!

 

-Carlo