Point the Factor So the Unit Cancels

You'll learnto build a conversion factor that cancels the old unit and finish in the unit asked.

A conversion multiplies by a factor equal to 1, oriented so the old unit cancels. Watch where careful students still lose points — converting square or cubic units with the linear factor, flipping the factor upside down, and answering in the units given instead of the units asked.

8 STEPS · 6 QUICK CHECKS · the old unit must cancel · finish in the asked unit · v3

old unit → new unit

Before you start

What you're looking at

A panel showing 60 min = 1 hr written as two factors, both equal to 1, beside a card of the four conversion moves.

The question

Which way up should the conversion factor go so the unit you are leaving cancels?

Watch for

Both fractions equal 1; watch which one puts the old unit on the bottom so it cancels cleanly.

What the symbols mean

Both 1 hr / 60 min and 60 min / 1 hr equal 1; multiplying by 1 changes the label, not the quantity.

Bring with you

Write the units next to the numbers and let them cancel like algebra — whatever unit is left over is the unit your answer is in.

Step 1 / 8