Every year, without fail, rounding has been one of the harder concepts to teach and one of the harder ones for kids to understand. Before starting our unit this year, I did a little research on Pinterest and came across this aha moment and wonderful idea from Mr. Elementary Math – vertical number lines! While yes a horizontal line will work, it’s confusing when we tell kids to round up and down because on a horizontal line you’re really moving left or right. This is where vertical number lines come in. You really are rounding up or down and visually it’s much easier for kids to see. Check out Mr. Elementary Math’s ideas for interactive number lines here…
Here’s how I started my rounding introduction….
So, we started by creating a list of multiples.To make it easier to figure out the two numbers that it was between, we created a list of multiples of ten and multiples of 100. While yes most kids are quite capable of counting by 10, it’s amazing how when you are talking about rounding some of those common skills go out the window.
Then, we created the anchor chart below and went through a few examples together… Here you can see the vertical number line in action. The lower number goes on the bottom of the vertical number line and the higher number goes on the top. Then the kids place the number and see which it is closer to. Then, they literally round down or up depending on where the number is. This made rounding so much easier for so many of my students!
To review – we played this rounding game called Roll It. This game is from Game for Gains and can be found….here….
Hope these tips are helpful for you! Vertical number lines have changed how I teach rounding and I’m so glad I found it!