Idea 8of 21Builds onPatterns that times by 10
Number strings for 7
How can one fact you know help with tens, tenths and hundredths?
Today you'll discover
- how 3 + 4 = 7 moves through the places
- the same for take-away
- how multiplying and dividing are partners
Think firstStart from a fact you know: 3 + 4 = 7
3 + 4 = 7. What is 30 + 40?
Decide first, then press Next. Look at what stays the same from line to line.
A column of number sentences: 3 + 4 = 7, then 30 + 40 = 70, then 0.3 + 0.4 = 0.7, then 0.03 + 0.04 = 0.07, each answer appearing in turn. The last step shows 7 × 3 = 21, 21 ÷ 3 = 7, 7 × 30 = 210 and 210 ÷ 30 = a question mark.
See the whole ideathe big idea and the key word, in one place
The big idea
One fact you know gives a whole string of facts: only the place of the digits changes.
One fact, moving
The same fact, moved through the places.
- ones3 + 4 = 7
- tens30 + 40 = 70
- tenths0.3 + 0.4 = 0.7
- hundredths0.03 + 0.04 = 0.07
Compare themMultiplying and dividing are partners: 7 × 3 = 21, so 21 ÷ 3 = 7 and 21 ÷ 7 = 3.
Key word
- number string
- a list of related number facts, each built from the one before
Ready to use it?
- Use a fact you know to add or subtract tenths and hundredths.
- Write the division partner of a multiplication fact.