Idea 6of 23Builds onThe price for one litre
Estimate to check a unit price
How can you tell if a unit price makes sense?
Today you'll discover
- how to round a price
- how to divide in your head
- how to catch a decimal slip
Think first6 granola bars for $5.94
A box of 6 granola bars costs $5.94. About how much is one bar?
Decide first, then press Next. Round the price to whole dollars before you divide.
A box of 6 granola bars with a tag: $5.94. Then a bar cut into 6 equal parts and the estimate: about $6.00 ÷ 6 = $1.00. Then the exact division $5.94 ÷ 6 = $0.99, close to the estimate. The last step asks about 3 tennis balls for $8.97.
See the whole ideathe big idea and the key word, in one place
The big idea
Round the price, divide in your head, and check the exact answer is close.
Round, then divide
$5.94 for 6: about $6 ÷ 6 = $1. $8.97 for 3: about $9 ÷ 3 = $3.
- Price$5.94
- Round$6.00
- ÷ 6about $1
Easy to get wrongA slipped decimal point makes an answer 10 times too big or too small. An estimate catches it.
Key word
- estimate
- a close answer found with rounded numbers, used to check the exact answer
Ready to use it?
- Estimate a unit price by rounding.
- Pick the unit price that makes sense.