1 1/2 as a decimal is 1.5.
To convert the mixed number 1 1/2 into a decimal, you first take the whole number part, which is 1. Then, you convert the fractional part (1/2) into a decimal. The fraction 1/2 is equal to 0.5. By adding these two parts together—1 (the whole number) and 0.5 (the decimal form of the fraction)—you get 1.5.