Middle School

Manipulating the Speed Formula

A short strategy intro, with letters instead of numbers. Start with s = d ÷ t, identify what you want to find, and use the same three rules as Isolating Variables to get it alone.

The 3 Rules

1
Isolate the variable
Get the one you are trying to find on a side by itself.
2
Use the inverse operation
If you want to move something to the other side, do the inverse operation (the opposite operation. example: + is the opposite of −).
3
Whatever you do to one side, you MUST do to the other.

Finds = dt

Find distance. Get d alone.

s = dt

Rule 1: Targeting

Which letter are we trying to isolate to find distance?

Manipulating the Speed Formula: a guide for parents

Grades 6–8 • Math • Free, no login

A short strategy intro: identify the variable, choose the inverse operation, and keep both sides balanced. Letters only, no calculations.

Kitchen Table Prompt

Ask: if you know how far the drive is and how fast you are going, which variable are you trying to find? Start from s = d ÷ t. Multiply both sides by t, then divide both sides by s to get t alone.

Standards this lesson covers

Common Core: MS-PS2-2 (Motion and Stability: use relationships among distance, time and speed to describe the motion of an object)

Texas (TEKS): TEKS 6.8C & 8.6B (Calculate average speed using distance and time measurements; describe and calculate how speed changes with distance and time)

Florida (NGSSS): FL NGSSS SC.6.P.12.1 & B.E.S.T. MA.6.AR.2 (Measure and graph distance versus time; write and solve one-step and two-step equations to represent relationships)

Virginia (SOL): VA SOL 6.13 & 7.12 (Solve one-step and two-step linear equations in one variable; represent relationships with equations)

North Carolina (SCOS): NC SCOS 6.EE.7 & 7.RP.2 (Solve real-world problems by writing and solving equations; recognize and represent proportional relationships between quantities)

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