How do you write ##12 3/10## as a decimal?

## 12 3/10 = 12.3##

Look at what you already know:

The whole number is 12, that will be written to the left of the decimal point.

The fraction has its denominator as a power of 10, which means it can be written as a decimal with 1 decimal place. ##3/10 = 0.3##

##:. 12 3/10 = 12.3##