The big ideaAdd the tens and the ones on their own rows. The order does not matter.
How it works
Every number comes apart into tens and ones, and each has its own row on the frame.
Add tens to tens on the top row, and ones to ones on the bottom row.
Tens first or ones first, the answer is the same.
A row with no beads is zero, so an empty row simply fills up.
The answer, 68: six tens and eight ones.
Example 1: Tens first
Put 43 on the frame: four tens and three ones.
Slide 2 tens across the top row: 4 + 2 = 6 tens.
Slide 5 ones across the bottom row: 3 + 5 = 8 ones.
43 + 25 = 68
6 tens and 8 ones is 68.
Example 2: Ones first
Put 34 on the frame.
Add the ones first: 4 + 2 = 6 ones.
Then add the tens: 3 + 6 = 9 tens.
34 + 62 = 96
9 tens and 6 ones is 96.
Example 3: An empty row
60 is six tens and no ones, so the ones row starts empty.
Add 9 ones: 0 + 9 = 9 ones.
Add 2 tens: 6 + 2 = 8 tens.
60 + 29 = 89
8 tens and 9 ones is 89.
Example 4: Check it makes sense
Ben has 26 stickers and Mia brings 33 more.
Tens: 2 + 3 = 5 tens. Ones: 6 + 3 = 9 ones.
26 + 33 = 59
Does it make sense? 20 and 30 make 50, and a few more is 59.
Words to know
tens row
The top row on a two-row frame. Each bead is worth ten.
ones row
The bottom row. Each bead is worth one.
place
Where a digit sits: in the tens or in the ones.
zero
A row with no beads slid across.
Watch out
Ones go with ones and tens go with tens. Never add ones to the tens row.
Only the beads slid across to the right count. Beads still on the left do not.
Check the size: 40 and 20 make 60, so 43 + 25 should be a little more than 60.
Try it
What is 51 + 27?
What is 34 + 62?
What is 50 + 38?
A frame shows 4 tens and 6 ones. Add 3 tens and 2 ones. What number is it?
Answers: 1. 78 · 2. 96 · 3. 88 · 4. 78
Try at homePick two numbers under fifty with no carrying, like twenty-four and thirty-five. Ask a grown-up to count them all, one by one, while you add the tens and the ones on their own, and see who finishes first. Then swap jobs!
For grown-upsLet your child say it aloud as they slide the beads: say the tens, say the ones, check it makes sense.
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