Idea 21of 21Builds onGraph the savings
Spending down, four ways
What do the four ways look like when money goes down?
Today you'll discover
- a shrinking pattern's rule and table
- an expression that takes away
- a graph whose dots drop
Think firstMaya has $60 and spends $8 a week
What kind of pattern is Maya's money?
Decide first, then press Next. Watch the money go down in every one of the four ways.
Three boxes: has $60 now, spends $8 each week, stop at $15 or less. Then the rule sentence, a table from week 0 at $60 down to week 6 at $12, the expression 60 minus 8x, and a graph whose dots drop to the right, with the week 6 dot ringed below a dashed line at $15.
See the whole ideathe big idea and the key word, in one place
The big idea
A shrinking pattern starts high and takes away the same amount each time.
Compare themGrowing: 5x + 15, and the dots climb. Shrinking: 60 − 8x, and the dots drop. Same four ways, opposite direction.
Easy to get wrongIn 60 − 8x the start comes first. 8x − 60 is a different rule, below zero at the start.
Key word
- representation
- one way of showing a pattern: a rule, a table, an expression or a graph
Ready to use it?
- Show a shrinking pattern as a rule, a table, an expression and a graph.
- Find when a shrinking pattern reaches its stop.