Seven counters in two trays. Four are in one tray. How many are hidden in the other?
Step 1: Let's Learn
Read it, or press Listen and follow the words.
Count up to the whole
Start at four and count until you reach seven. Five, six, seven. That is three counts, so three are hidden.
Why counting up works
The hidden ones are exactly the gap between what you can see and the whole. Counting the gap measures it.
Check it
Four and three makes seven. It fits, so the answer is right.
This is a different kind of question
You are not taking anything away. You are finding a part you cannot see. Subtraction answers that too.
Step 2: Try It Yourself
Tap and try it out.
7
4
3
Tray you can see
Hidden tray
4 and 3 make 7.
Step 3: Watch an Example
One step at a time.
Watch Mia Find the Hidden Part
Mia has seven stars. Four are showing.
- Step 1
She starts at four, the part she can see.
Step 4: Your Turn
Practice makes it stick.
The Hidden Marbles
Problem 1 of 1
Nine marbles. Six on the table. How many in the bag?
Find What Is Missing
1 of 4
5 + ? = 8
2 of 4
2 + ? = 6
3 of 4
7 + ? = 7
4 of 4
4 + ? = 9
Step 5: Quick Check
Show what you know.
Question 1 of 1
6 + ? = 10
What You Learned
- Sometimes you know the whole and one part.
- Count up from the part you know.
- Check by putting the parts back together.