The big ideaOne whole is ten tenths. Each bead on the row is one tenth.
How it works
Split a whole into ten equal parts, and each part is one tenth.
A row of ten beads is the whole, and each bead is one tenth.
We write tenths with a point: 0.2 is no wholes and two tenths.
Ten tenths trade for one whole, and we write it 1.0.
Six of ten squares eaten: six tenths.A full row: ten tenths make one whole, 1.0.
Example 1: Two tenths
The chocolate bar has ten equal squares.
Mia eats two squares, so two beads slide across.
Two out of ten parts is two tenths.
We write it 0.2.
Two tenths: 0.2.
Example 2: Adding tenths
Start with two tenths: two beads across.
Add four tenths: slide four more beads across.
Six beads are across, so there are six tenths.
0.2 + 0.4 = 0.6.
Example 3: Taking away tenths
Start with six tenths: six beads across.
Slide two beads back.
Four beads are left, so there are four tenths.
0.6 − 0.2 = 0.4.
Example 4: Which is more?
Compare two tenths and six tenths.
More beads across means more.
Six tenths is more than two tenths, even though both start with zero point.
Example 5: Ten tenths
Slide every bead across until the row is full.
Just as ten ones trade for a ten, ten tenths trade for a whole.
We write it one point zero: 1.0.
Words to know
tenth
One of ten equal parts of a whole.
decimal point
The dot in 0.2. The beads slid across are counted after it.
whole
All of it. Ten tenths make one whole.
decimal
A number written with a point, like 0.4.
Watch out
The zero in front of 0.2 says there are no whole bars yet.
0.2 is two tenths, not two wholes.
This frame shows only tenths: one row of ten beads.
More beads across means more tenths, so 0.6 is more than 0.2.
Try it
A bar has ten squares and Ben eats four. How many tenths is that?
How many tenths make one whole?
What is 0.3 + 0.4?
What is 0.8 − 0.5?
Answers: 1. Four tenths, 0.4 · 2. Ten · 3. 0.7 · 4. 0.3
Try at homeAsk a grown-up to help you cut or fold a strip of paper into ten equal parts. Colour four of the parts. Then say how many tenths are coloured, and how many are not.
For grown-upsFold or cut a paper strip into ten equal parts and colour four of them. Say how many tenths are coloured and how many are not.
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