Recognize Proportional Relationships

How the lesson starts: Recognize Proportional Relationships

Feeding time!
Hi there! Kai is the penguin keeper at the zoo. Every penguin gets 3 fish at lunch. Here are 2 penguins, and here are their 6 fish. Kai wonders: if more penguins waddle in, does the fish count grow in a fair, steady way?
Same ratio every row
Kai makes a table. 1 penguin, 3 fish. 2 penguins, 6 fish. 4 penguins, 12 fish. Now divide fish by penguins in every row. It's always 3! That's proportional. If the ratio changes, like (1,4) then (2,7), it's not proportional.
Fill the missing value
The seals get the same fish each. The table says 1 seal, 4 fish, and 2 seals, 8 fish. How many for 5 seals? Find the ratio: 8 ÷ 2 = 4 fish per seal. Then 5 × 4 = 20. Watch out: don't just add 4 to 8. The jump from 2 to 5 is bigger than one step.