Input & output tables: finding the output
About this video
A table shows Manny's age and his older sister Maria's age. The video finds the rule (Maria is always 5 years older, so add 5), checks it on every row, and uses it to find that Maria is 17 when Manny is 12.
You'll be able to
- find the rule that turns an input into an output in a table.
- check a rule against every row of a table.
- use a rule to find a missing output.
Key words
- input
- The number you start with and put into a rule.
- output
- The number you get after you use the rule on the input.
- rule
- The step that always changes the input into the output, like add 5.
Transcript
- [Instructor] We are told Maria is older than her brother Manny. The table shows Manny's age and Maria's age. This table's right over here. How can we find Maria's age when Manny is 12 years old? So essentially, when Manny is 12, how old is Maria? So pause this video.
Have a go at that before we do it together. Okay, so we see that when Manny's 3 years old, Maria is 8 years old, or another way to think about it is Maria is 5 years older than Manny. You take Manny's age as an input. Add 5 to it. You get Maria's age. Let's see if that holds up, and it should because if someone's 5 years older, people don't change.
They're going to continue to be 5 years older as they age together, and we see that 6 plus 5 is 11. 9 plus 5 is 14, so Maria's age when Manny is 12. We're just going to add 5 to that. 12 plus 5 is 17 years old.
Video © Khan Academy, used under CC BY-NC-SA. Watch on Khan Academy. Puzzicle is not affiliated with Khan Academy.