Equivalent Ratio Tables

How the lesson starts: Equivalent Ratio Tables

Ruby's lemonade stand
Hi there! Ruby runs a lemonade stand. Her secret recipe uses 3 lemons for every 5 cups of water. Today a huge crowd is coming! How can she make more lemonade that tastes exactly the same? A ratio table will help.
Build a ratio table
The first row is the recipe: 3 lemons, 5 cups. Double it: 6 lemons, 10 cups. Triple it: 9 and 15. Four batches: 12 and 20. Every row tastes the same, because both numbers were multiplied by the same multiplier. 3 to 12 is times 4, so 5 to 20 is times 4 too.
Let's fill a table
Ruby's new mix: 3 cups of juice go with 6 ice cubes. What goes with 5 cups? 3 times what is 5? That's not a whole number! Look across the row instead: 3 × 2 = 6, so the ice is always 2 times the juice. 5 × 2 = 10, and 9 × 2 = 18.