Multiplying decimals is easy and even fun. To multiply decimals, you have to multiply them like regular numbers without paying attention to the dots.
When you get the answer, you must separate the whole part from the fractional part with a dot. To do this, count the number of digits after the dot in both fractions, then count as many digits to the right in the answer and put a dot.
Example 1. Find the value of the expression 2.5 × 1.5
Multiply these decimals as regular numbers, ignoring the dots. To ignore the dots, you can pretend for a while that they do not exist at all:
We got 375. In this number it is necessary to separate the whole part from the fractional part with a dot. To do that, count the number of digits after the point in fractions 2.5 and 1.5. The first fraction has one digit after the point, and the second fraction has one digit after the point. The total is two digits.
We return to the number 375 and start moving from right to left. We need to count two digits to the right and put a dot:
The answer is 3.75. So the value of the expression 2.5 × 1.5 is 3.75
2.5 × 1.5 = 3.75
Example 2. Find the value of the expression 12.85 × 2.7
Multiply these decimals without paying attention to the dots:
We got 34695. In this number you need to separate the whole part from the fractional part with a dot. To do this, count the number of digits after the dot in fractions 12.85 and 2.7. Fractions 12.85 have two digits after the dot, fractions 2.7 have one digit - three digits in total.
Go back to the number 34695 and start moving from right to left. We need to count three digits to the right and put a dot:
The answer is 34.695. So the value of the expression 12.85 × 2.7 is 34.695
12.85 × 2.7 = 34.695
2. If you find an error or inaccuracy, please describe it.
3. Positive feedback is welcome.