It's just a jump to the left,
Then a step to the right ...

"#20 | Posted by LampLighter
Another way I was taught was to multiply C by 9, divide by 5, and add 32.
A little easier without a calculator ...
#22 | POSTED BY AMERICANUNITY AT 2025-08-17 01:49 AM"

When dealing with 10's of C, it's even easier to multiply by 2 and divide by 10 (move the decimal point one place to the left) before multiplying by 9 and then adding 32.

One learned to evaluate math problems and then do easy/simple calculations in one's head in the days before calculators. It's a very useful skill.

"Because something is happening here but you don't know what it is
Do you, Mr. Jones?"

- Ballad of a Thin Man by Robert Zimmerman