Idea 14of 23Builds onExpanded form shows each digit's value
Split a number to multiply it
How can you work out 6 × 47 without a long calculation?
Today you'll discover
- how to split 47 into tens and ones
- how to multiply each part
- why the parts add up
Think firstA rectangle 6 squares by 47 squares
Which is the same as 6 × 47?
Decide first, then press Next. Split the bigger number into tens and ones.
A rectangle of small squares, 6 rows of 47. A dashed line cuts it into a piece 40 wide and a piece 7 wide. Under the pieces: 6 × 40 = 240 and 6 × 7 = 42, then 6 × 47 = 240 + 42 = 282. The last step asks for 7 × 36.
See the whole ideathe big idea and the key word, in one place
The big idea
Split one number into parts, multiply each part, then add the answers.
For example6 packs of 47 hockey cards: 6 × 40 = 240 cards and 6 × 7 = 42 more, so 282 cards.
Key word
- distributive property
- multiplying a sum is the same as multiplying each part and adding: 6 × 47 = 6 × 40 + 6 × 7
Ready to use it?
- Split a number into tens and ones to multiply.