Addition can be done in any order. The total does not care.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
Look for friendly pairs
In 23 + 17 + 45, the 23 and 17 make 40. Do that pair first.
Keep a running total
Add two, write the answer, then add the next one to it.
You may add them in any order
Adding 8 + 5 + 2 + 5 can be done in any order at all, and the total never changes. That freedom is a rule of addition, and it lets you rearrange a list to make it easier before you start.
Look for friendly pairs
In 8 + 5 + 2 + 5, the 8 and 2 make 10 and the two 5s make another 10. So the total is 20, found in two easy steps instead of four fiddly ones. Scan any list of numbers for pairs that make ten before adding left to right.
Cross off as you go
When you rearrange a list it is easy to use a number twice or skip one entirely. Cross each number off as you use it. With four or more addends this small habit is the difference between a reliable method and a lucky one.
Step 2: Try It Yourself
Tap and try it out.
0 + 23 + 17 + 45 = 85
The round dot is where you started. The square is where you landed.
Step 3: Watch an Example
One step at a time.
Watch Ana Reorder
Ana adds 23 + 17 + 45 + 15.
- Step 1
She scans for pairs that finish on a ten.
Step 4: Your Turn
Practice makes it stick.
Four Boxes
Problem 1 of 2
Boxes hold 12, 28, 15 and 25 apples. How many apples in all?
apples
Three Days
Problem 2 of 2
Leo read 34, 26 and 18 pages on three days. How many pages in all?
pages
Find the Friendly Pair
1 of 3
15 + 25 + 30 = ?
2 of 3
18 + 22 + 14 + 16 = ?
3 of 3
11 + 29 + 13 + 27 = ?
Step 5: Quick Check
Show what you know.
Question 1 of 2
13 + 27 + 20 = ?
Question 2 of 2
Does the order you add in change the total?
What You Learned
- Add several numbers in whichever order is easiest.
- Look for pairs that finish on a ten.
- The total never changes, only the work.