Idea 15of 23Builds onRounding picks the closer tenth
Count the hundredths to each side
How can you tell exactly how close 56.23 is to each tenth?
Today you'll discover
- how to count hundredths on the line
- why the two counts add to 10
- how the counts decide the rounding
Think first56.23 between 56.2 and 56.3
How far is 56.23 from each of its tenths, 56.2 and 56.3?
Decide first, then press Next. Count the small marks, not the digits.
A number line from 56.2 to 56.3 with a mark for every hundredth and a dot at 56.23. Brackets above it read 3 hundredths back to 56.2 and 7 hundredths on to 56.3. Then 56.2 is ringed: 56.23 rounds to 56.2. Then 56.28: 8 hundredths back, 2 on, rounds to 56.3. The last step shows 0.09.
See the whole ideathe big idea and the key word, in one place
The big idea
Count the hundredths to each neighbouring tenth. The smaller count shows the closer one.
56.23 and 56.28
56.23: 3 back, 7 on, so 56.2. 56.28: 8 back, 2 on, so 56.3.
- 56.2356.2
- 56.2856.3
Easy to get wrongCount from the tenths either side, not from the whole number. 56.23 is 3 hundredths from 56.2, not 23.
Key word
- distance
- how far apart two numbers are on the line, counted here in hundredths
Ready to use it?
- Count how far a decimal is from each neighbouring tenth.
- Round to the nearest tenth.