Question

how u understood where the add the decimal point?

Answer 1

Answer:

here is a simple trick

Step-by-step explanation:

Addition with Decimals

To add decimals, write the numbers in a column, and make sure that the decimal points are aligned. To keep the decimal point in your sum, place a decimal point directly below the decimal points in the addends.

example in image 1

Subtraction with Decimals

To subtract decimals, begin by writing the numbers in a column, with the decimal points aligned. If necessary, add zeroes as place holders to make sure there are values in each column. Subtract from right to left. Write the decimal point in the difference directly below the decimal point in the subtrahend. You can check the answer by adding.

example image 2

Division with Decimals

if the division is with 10 or multiples of 10 then the simplest way to remember it is shift the decimal to the left exactly the times 0 is there

example

$10 \div 100 \\ \\ = 0.10$

just like here we shifted the decimal to two places on the left when it was divided by 100 because 100 has 2 zeroes