Hint:At first read the digits to the left of the decimal point as a whole number.For decimal we will use point.The digits to the right of the decimal point should be written as individual digit.
Complete step-by-step answer: The given decimal number is $1.20$ We have to write it in words. We will follow a few steps to write the decimal in words. Step 1: At first read the digits to the left of the decimal point as a whole number. Here the digit to the left of the decimal point is $1$. So, we can write only one.
Step2: For decimal we will use the word “point”.
Step 3: The digits to the right of the decimal point should be written as individual digits. We can not read it as a whole number. Here, we have $0.20$ , so we will write it as point two zero.
Therefore, the word form of the decimal number $1.20$ is one point two zero.
Note:In mathematics, a decimal number can be defined as a number whose whole number part and the fractional part is separated by a decimal point. The dot in a decimal number is called a decimal point. The digits following the decimal point show a value smaller than one.