Rearranging Formulas

Lesson 6 of 12 · 7 min · Free, no account needed

What you will learn

A formula is an equation with letters. Rearranging it means getting a different letter alone.
Do the same to both sides: d = s × t, divide both sides by s, and t = d ÷ s.
Undo the outside step first, just like rewinding a machine: y = mx + b gives x = (y − b) ÷ m.

Speed = distance ÷ time. You know the speed and the time. Which formula gives the distance?
Drive. Then fix the distance.
Turn speed and time and watch the distance. Then fix it at 120 km and find the speed for a 2 hour trip.
Get t alone in d = s × t.
Drag an action onto the formula. It lands on both sides at once.
That's rearranging a formula.
A formula is an equation with letters: d = s × t.
Rearranging gets a different letter alone. Do the same to both sides: divide both by s and you get t = d ÷ s.
It's the undo machine again: t goes in, ×s makes d. Undo ×s with ÷s to get t back.
Rewind y = mx + b with letters.
x goes in, gets multiplied by m, then b is added. Step back to find x from y.
Build a game converter: level in, coins out.
Drag two stations onto the belt, like × 5 then + 20. Tap a level to test it.
Game: formula relay.
Free each target letter as fast as you can. The last formula is your converter.
This trip planner prints 0.5 hours. It should print 2.
120 km at 60 km/h. Fix the formula for time.
One formula, three jobs.
Tap d, s and t.

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