How do you put 3 23/66 as a decimal?

Convert the fractional part to a decimal, then add the result to the whole number part.

3.348

In order to change mixed fractions into a decimal you will at first divide the top number by the bottom number, otherwise affectionately known at the numerator and the denominator.

23 : 66 = 0.348

Next, you will just add the whole number to the decimal.

3 + 0.348 = 3.348 or if you'd like to round, 3.35

Therefore, your decimal form would be 3.35.