The big ideaTen is made of two parts. Take one part away, and the other part stays.
How it works
A full row is ten beads, all across.
Slide back the beads you take away. The rest stay across.
Ten is made of two parts: take one part away and the other part stays.
With two rows, take ones back from the bottom row. The ten stays.
Ten beads across: a whole row.17 on two rows: one ten and seven ones.
Example 1: Ten take away five
Ten beads are across. Mia wants five.
Slide five beads back.
Five beads stay across.
10 − 5 = 5
Ten take away five leaves five.
Example 2: Ten take away nine
Ben takes nine beads from the ten.
Slide nine beads back.
Only one bead stays across.
10 − 9 = 1
Ten take away nine leaves one.
Example 3: Ten take away three
Ten beads are across.
Slide three beads back.
Seven beads stay across.
10 − 3 = 7
Ten take away three leaves seven.
Example 4: 17 take away 4
Show 17: one ten on the top row and seven ones on the bottom row.
Slide four ones back from the bottom row.
The ten stays where it is, with three ones.
17 − 4 = 13
17 − 4 = 13
Words to know
take away
To slide beads back.
leaves
What is still there after you take away.
a ten
A full row of ten beads.
Watch out
Take ones back from the bottom row. The ten stays where it is.
Count the beads still across, not the ones that slid back.
Taking all ten away leaves none across.
Try it
What is 10 − 2?
What is 10 − 6?
What is 17 − 4?
All ten beads slide back. How many stay across?
Answers: 1. 8 · 2. 4 · 3. 13 · 4. None
Try at homeAsk a grown-up to help you find ten small things, like spoons or blocks. Take some away and say how many stay, then put them back and try again with a different number.
For grown-upsFind ten small things such as spoons or blocks. Take some away and say how many stay, then put them back and try a different number.
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