Grade 6

Rules and tables

Functions: one quantity depends on another. Part of below zero and beyond.

Rules and tables

Functions: one quantity depends on another · Alberta Grade 6 · maddyhelps.com

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A candle is 10 cm tall and burns down 2 cm every hour. The hours are the independent variable; the height depends on them. Fill in the table, plot the points (hours across, height up), and write the rule.

Hours, t	0	1	2	3	4	5
Height (cm), h	10

h =

t = 3: h =

h = 2: t =

Which is independent and which is dependent: the number of pizzas ordered, and the total cost?

Which is independent and which is dependent: how long a car has been driving, and how far it has gone?

For the grown-up

Rules and tables

Heights: 10, 8, 6, 4, 2, 0 cm. Rule: h = 10 − 2 × t. At t = 3, h = 4; h = 2 when t = 4. The points fall in a straight line going down. Pizzas is independent and cost depends on it. Time is independent and distance depends on it.

Working backwards — which hour makes the height 2 cm? — is what Alberta's outcome calls finding the independent variable from the dependent one. Counting down the table works; so does solving 10 − 2 × t = 2.

Why this matters is on the below zero and beyond page. More sheets