I'll start by doing Quick Images, a quick subtilizing within 10 game. The game is listed first as Numbers to 10 on the Ten Frame. This online tool is free and excellent for helping students build fluency with numbers that add to ten, and also helps them use base 5 to subitize quickly. I use this routine throughout the year to help students build a strong number sense!
Every time I show one, I show it for 2-3 seconds. I usually show it twice, at about 2 seconds each, then I call on one student to tell me how many and quickly to tell me how they know. Then I ask the question: How many more to make 10?
We know lots of number facts in our brains by now-we just found all these ways to make 10! Today you are going to see if you can use number facts to help you solve problems quickly.
Your thinking job today is: What strategies can I use to make it easier to add 3 numbers? What friendly number sentence is hiding in that number sentence?
Present Problem: A little girl named Elizabeth went to the store. She bought a bunch of candy. She bought 5 lollipops, 5 chocolates and 3 pieces of bubblegum. How many candies did she buy in all?
I’ll have one student model for now, using a different color of cube for each type of candy.
Let’s write what we just did on our strategy chart so we can look back to it in a minute. While I’m writing, tell your partner. How did we solve this problem?
See attached Strategy Chart.png for how I present this to kids. The circle under 5+5 is what I call a "bunny". We talk about how we can put 5+5 together, draw bunny ears and then write 10 in the bunny.
After I draw the strategy chart, we will retell the strategy as a group.
For the student share time, students will work with a partner. Each partner group needs 3 towers of cubes; each tower is a different color. They also need a double ten frame. Mathwire has one for free!
Present Problem: I’ll do as many problems as I have time for. For each problem, students will determine together what color will represent each part of the problem.
Guiding Questions after each problem:
Students get 3 story problems to solve. Most students, because this is the first day of this work, will need the first set of problems, with sums under 20.
Intervention idea: Provide a double ten frame for students to use during problem solving. It will help them see how they could group two numbers into a ten.
Extension problems: These problems will probably be for very few students. Students in this group apply understandings of base ten to group larger numbers. These are students who are consistently using mental math to add numbers on the decade!
Watch one student explain how she solved the extension word problems!
Word problems are attached!
Students share one problem with a partner. Student explains how he/she solved, particularly focusing on if a friendly number sentence was used!