Yep....we're starting to work with double digits in our first grade classrooms.
The addition wasn't so bad....but the subtraction is "a little challenging" for some of my firsties!
I've created a little game with a deck of cards to help make the practice time with my small groups a little more fun and exciting.
First small group participant takes two cards and creates the highest double digit from those two cards...let's say they pull a 5 and an 8. They announce to the group that the double digit we'll be starting with is 85. Everyone in the group uses their dry erase markers to write the 85 on their boards (you could use paper and pencil here just as well).
Then I choose the next card from "My Special Deck of Cards" making sure that it's a card lower than the first digit written...I can choose one card and say let's make it ____ groups of ten...for instance if I pulled a 4....I might say, how do we write the number that is 4 tens...40...or I can choose two number that I know will not need to be regrouped and form a smaller number...for instance 3 and 2...would make 32.
Then we practice lining up our numbers right under the 85.
We add the sign that means to take away....subtract...minus...and then fly to Japan (because the read from right to left) and subtract the ones column first...then go to the left and subtract the tens column.
We end the game by saying the entire number sentence together....85 take away 40 equals (is the same as) 45.
Hope this makes sense....
I've got a free download of one of our practice sheets for this concept on my blog...hop on over to download it and check out the wonderful time the Tennessee Bloggers had at their Blog Luncheon in Lebanon, TN yesterday :)
Enjoy your day!