Life Sized Subtraction

When I taught first grade, I remember my kids had a little difficulty understanding that the greater number had to come first in a number sentence when subtracting.  I know that kids can memorize like nobody’s business, so I think it’s EXTREMELY important to get them to understand WHY so they know how to apply as the skill progressively becomes more challenging {how’s that for a long, grammatically incorrect sentence?!?!} We’ve talked about the symbol we use for subtraction and lots of key words, so it was time for some hands-on fun.

To introduce the concept, we started with a fun…SUPER simple…hands-on, whole group activity that my kids absolutely ADORED.  All that’s needed is 2 pair of dice, dry erase boards/sleeves OR something to write on, and manipulatives.  I gave each of my kids a dry erase sleeve {I LOVE these things!!!}, marker, and a wipe.  {You could always use a clear page protector, too!}  Then I set out some snap cubes {to use as counters} in front of each kiddo.  To start the activity, I passed out the 2 sets of dice to two of my little friends then asked both of them to roll the dice in their “bubble” :)  Before I let my kids help with this, I modeled it for them 3-4 times so they knew exactly what to expect!

 

After they rolled the dice, they repeated the amount they rolled and then we did a little quantity discrimination to determine the GREATEST number our of the two.  Once we determined the greatest number, the kids counted out that amount of snap cubes.  Then I reminded the kids to remove the smaller amount from the bigger amount.  Each time we did this, I reminded them that we ALWAYS start with the bigger number when subtracting because you can’t take away more than you already have.  Then we wrote our number sentences to match.  Loved that I was quickly able to assess understanding and then follow-up as needed!

 

We’re really getting our feet wet!!!  Speaking of feet, we also did a little life-sized subtraction with a tens frame, a die, and our own two feet!  I drew out a big tens frame on butcher paper and had 10 of my friends fill the frames.  Then we rolled a die and removed that amount of friends from the tens frame.  The kids loved it…they were hilarious!!  We practiced making number sentences, too. Lots of hands-on…and feet-on?!?!…FUN subtracting!!!!

I’ll be back tomorrow talking about my math tubs and how they work in my classroom…and stay tuned for a little re-cap of last weekend’s Houston Blogger Meet-up!  Such talented, sweet teachers in this city!