Are you wondering how to build number sense into your math block? Here are some easy tried and true ways I've found to do just that.
Building Number Lines
Building number lines gets students thinking about numbers and quantity. You can build number lines counting by 1s, 2s, 5s, 10s, etc. You can cross the decade, start at numbers other than 0, and even go backwards. When I do this, I do not tell students the parameters of the number line. I simply pass out folded index cards with numbers on them. I ask the children to keep their card top secret. Then, I instruct students, one at a time, to place the number where they believe it goes on the number line. When it is their turn to put their card on the number line, students may rearrange the other cards. Not only is this a great way to get students up and moving, it involves all students and forces them to think about numbers. Even if a student does not have a card, they may raise their hand to rearrange the cards.
Counting the Tens Way
Counting the "tens way" is a neat way for students to decompose numbers. You begin counting the traditional way until you get to ten. Ten is "one ten", eleven is "one ten, one", twelve is "one ten, two", thirteen is "one ten, three", fourteen is "one ten, four", etc. Twenty becomes "two tens", twenty one is "two tens, one", etc. One hundred is either "ten tens" or "one hundred". Students really grasp place value when you teach them to count this way.
Number Rack Cover Up
To begin with, show students the number rack so they can see it in its entirety. Then slide some beads over and cover up. Student need to figure out how many are covered up.
Here students see 4 white so they know 5 red and 1 white, or 6, are covered up.
Here students see 5 white and two red so they know 3 reds are covered up.
Here students see 2 white so they know 3 white and 5 red, or 8, are covered up.
Here students see 5 white and 4 red so they know 1 red is covered up.
You can use a twenty rack, too, to help students problem solve for larger numbers. This quick and easy activity is a great way for students to "see" missing addends.
Number Talks are a short lesson that provides students with meaningful practice with computational fluency and problem solving. In the primary grades the expectation is that they will use number relationships and the structures of numbers to add and subtract. I love to use pictures in my number talks. I try to use pictures where students can subitize, problem solve, nd communicate ways to solve problems.
Let's look at the picture above. Imagine we asked students to tell us how many stars there are. I see two groups of 4 to the right of the highest peak. I see three and three to the left of the peak. Now I must put those numbers together to figure out how many stars there are. When we ask students how they solved this problem, some students will say they counted each star, which is a fairly inefficient way to go about it. Others will say they counted by two, some may say they counted up, etc. I record all of the ways students came up with. Then, we discuss the most efficient ways to get students thinking about more than one way to solve a problem. The whole activity takes 5-10 minutes and is a quick, easy way to incorporate problem solving and computational fluency into your math block.
If you want to try this out in your classroom, try this picture out. You can get it and two others here.
Some of these ideas are from my Subitizing pack. You can get that here.
What are some ways that you build number sense? Please share in the comments - - I would love to hear from you!