There are two main temperature scales:

They both measure the same thing (temperature!), but use different numbers:

The scales start at a different number (0 vs 32), so we will need to add or subtract 32

The scales rise at a different rate (100 vs 180), so we will also need to multiply

and100180can be simplified to59, so we get this:

CtoF:Divide by 5, then multiply by 9, then add 32

FtoC:Subtract 32, then multiply by 5, then divide by 9

Example: Convert 25 Celsius(a nice warm day)to Fahrenheit

We can swap the order of divide and multiply if we want, but dont change the add or subtract. So this is also OK:

(Same answer as before, was it easier or harder this way?)

Fahrenheit to Celsius: (F − 32) 59= COther Methods That WorkUse 1.8 instead of 9/5

9/5 is equal to 1.8, so we can also use this method:

Fahrenheit to Celsius: (F − 32) / 1.8 = C

To make 1.8 easier we canmultiply by 2 and subtract 10%, but it only works for C to F:

Since both scales cross at−40(−40 C equals −40 F) we can:

To remember 9/5 for C to F thinkF is greater than C, so there are more F than C

Fahrenheit to Celsius: Subtract 30, then halve

Footnote:Temperatureis a measure of how fast an objects particles are moving.