TEKS & Objectives
7.3 Number and operations. The student applies mathematical process standards to add, subtract, multiply, and divide while solving problems and justifying solutions. The student is expected to:
7.3.A add, subtract, multiply, and divide rational numbers fluently; and
7.3.B apply and extend previous understandings of operations to solve problems using addition, subtraction, multiplication, and division of rational numbers.
We will strengthen our number sense.
I will add and subtract positive and negative integers using a number line.
1. Complete warmup.
2. Add and subtract on a number line.
We’ll do these together as a class.
First, let’s try addition:
Now, let’s take a crack at subtraction.
3. Watch videos and break it down.
Let’s break it down…
- We can use ten frames to keep it visually simple.
- Remember, always move from left to right (<–)
- We’ll start with the number 13. 10 blocks will fit in our 10 frame.
- There are 3 blocks that don’t fit.
- We have to move our 10 blocks to the left (<–) into our 10s column.
- Using base 10 manipulatives, we would trade 10 blocks for a stick that already has 10.
- After we move our 10 blocks over, it should look like this:
- Now we have room for our last 3 blocks.
- It’s now much easier to see that we have 13, because 1 is in the tens column and 3 are in the ones column.
- Now lets look at a problem with bigger numbers and no ten frame.
- We’ve added a hundreds column and taken away the ten frame.
- On the top, we have 135 blocks: 1 hundred (flat), 3 tens (long) and 5 blocks.
- Underneath, we added our next number 278: 2 hundreds (flats), 7 tens (longs) and 8 blocks.
- We have 13 blocks. That’s more than 10. We need to move 10 blocks into the tens column and exchange them for a 10 stick (a long).
- That will leave three 1s in the ones column.
- Once we do that, we’ll have 11 sets of 10. That’s more than 10. Ten 10s are 100. So we need to move ten 10s into the hundreds column. That will add one flat of 100.
4. Let’s try it together.
We’ll use a base 10 mat.
5. “Comaring Negative Numbers”
8. Complete assignment at Brainzy.
Roadblock: Addition Within 20
Place Value Game Show
Three digit addition: Train Edition
Three digit subtraction: Train Edition
Look for the assignment with today’s date.
Find access codes here.