Ignore the decimal point for now. We’ll come back to it later. Just multiply by 12:
Count how many digits there are after the decimal point in the two numbers 1.735 and 1.2. The first has 3 and the second has 1, so the product has 3+1=4. Count from the end of the product 4 places and insert the decimal point: 2.0820. You can leave out the last zero because it doesn’t change the value: 2.082.
Another way to find out where the decimal point goes is to estimate the product by rounding the numbers. So 1.7 is about 2 and 1.2 is about 1, and the product of 2 and 1 is 2. So the product needs to be about 2. Put the decimal point in the product to make this so. Placing it after 2 is therefore correct: 2.082.