In 3rd grade we must teach rounding on a number line. I used a wonderful supplement by Blair Turner to introduce rounding on a number line. She had such a real-work connection that my kids really grasped the concept.
Now my kids need practice.
Sure, I could print of paper copies of number lines and have them plot and search.
But where’s the fun in that?
I gave my kids a set of cards. We started out with a set from 1-100 counting by tens.
They quickly ordered themselves from least to greatest.
After that, I chose one student to be the plotted number. I gave them a whiteboard with a number written on it. He/she stood up and help up their white board. We then discussed between what two endpoints would this number most likely fall between.
THEN, I chose one student to be the midpoint. I gave them a whiteboard and we discussed what number is the halfway distance. That student wrote the number on the whiteboard and stood in the center of the endpoints. After a few rounds of this activity we began to notice a pattern with the halfway distance markers.
Would our plotted number fall before or after that number? We then placed our plotted number person to the appropriate part of the number line. Would it be closer to 6,500 or closer to 7,000 on the number line?
This is GREAT to reinforce vocabulary.
My kids really had to explain themselves with their thinking.
“6,900 would be close to 7,000 on the number line because the 9 in the hundreds places tells me that it is only 100 away from 7,000 and 400 away from 6,500. So I know that 6,900 rounds to 7,000”.