Idea 13of 21Builds onSay the rule
Input, rule, output
How does a rule turn one number into another?
Today you'll discover
- what an input and an output are
- how to follow a two-step rule
- how to find the output for 10
Think firstIn 0, out 0. In 1, out 5.
What comes out when 6 goes in?
Decide first, then press Next. Follow one number in at the top and out at the bottom.
A machine on the left with a number going in at the top, a rule card in the middle and a number coming out at the bottom; a table of inputs and outputs on the right. First the rule card shows a question mark and only two outputs are filled in. Then the rule, multiply by 5, is shown. Then a two-step rule, multiply by 3 then add 3, with the output for an input of 10 set apart at the bottom of the table.
See the whole ideathe big idea and the key word, in one place
The big idea
A rule turns each input into its output, the same way every time.
Compare themInput: the number that goes in. Output: the number after the rule is done to it. In a table, inputs go on the left and outputs on the right.
Easy to get wrongTwo-step rules go in order. For multiply by 2, then subtract 1, the input 10 gives 20 first and then 19, not 18.
Key words
- input
- the number you start with, before the rule is done to it
- output
- the number you get after the rule is done to the input
Ready to use it?
- Complete a table of inputs and outputs from a rule.
- Find the output for an input of 10.