Idea 9of 24Builds onOne array, four facts
Times 0.1 is one tenth
What happens to a number when you multiply it by 0.1?
Today you'll discover
- what × 0.1 means
- where each digit moves
- why the answer is smaller
Think first50 in a place-value chart
What is 50 × 0.1?
Decide first, then press Next. Follow each digit from the top row to the bottom row.
A place-value chart from hundreds to hundredths with a dot between the ones and the tenths. 50 sits in the top row. Arrows take each digit one column to the right, and the digits slide into the bottom row as 5.0, the 0 faded. Then 36 × 0.1 becomes 3.6, and the words say × 0.1 is the same as ÷ 10. The last step shows 245.
See the whole ideathe big idea and the key word, in one place
The big idea
Times 0.1 takes one tenth: every digit moves one place to the right.
Compare them× 10: every digit moves one place left, so the number gets bigger. × 0.1: every digit moves one place right, so it gets smaller.
Easy to get wrongThe decimal point stays put; the digits move past it. Do not just write .1 on the end.
Key word
- tenth
- one of 10 equal parts of a whole, written 0.1
Ready to use it?
- Multiply a whole number by 0.1 in your head.
- Explain where each digit moves.