1.20 is a decimal number representing one whole and twenty hundredths. 1. To understand 1.20, break it down into parts: the number to the left of the decimal point is the whole number part, which is $1$. 2. The digits to the right of the decimal point represent fractional parts. Here, 20 means twenty hundredths because it is two digits after the decimal point. 3. This means the number can be expressed as $$1 + \frac{20}{100} = 1 + 0.20 = 1.20$$ 4. In simpler terms, 1.20 is the same as $1$ and $20\%$ more, or 1 plus 0.20. Final answer: $1.20$ is a decimal representing the quantity one and twenty hundredths.