The missing number can be at the start, the middle, or the end.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
Look at what you do know first. Then work out what is left.
The box can sit anywhere
? + 6 = 14 and 8 + ? = 14 and 8 + 6 = ? are all real questions. Where the gap is changes how you find it, not whether you can.
Read before you calculate
Find which part is missing — a part or the whole — before choosing a method. Starting to calculate first is how the wrong operation gets used.
Step 2: Try It Yourself
Tap and try it out.
9 and 6 makes 15.
Step 3: Watch an Example
One step at a time.
Watch Ana Find the Box
Ana sees 9 + ? = 14.
- Step 1
She knows one part is 9 and the whole is 14.
Step 4: Your Turn
Practice makes it stick.
Saving Up
Problem 1 of 1
Ben has 8 coins. He needs 13. How many more does he need?
coins
Fill the Box
Use what you know to find what is missing.
1 of 3
9 + ? = 13
2 of 3
? + 6 = 14
3 of 3
15 − ? = 8
Step 5: Quick Check
Show what you know.
Question 1 of 2
8 + ? = 12
Question 2 of 2
13 − ? = 9
What You Learned
- The missing number can be anywhere.
- Start from what you already know.
- Make a ten on the way if it helps.