When you enter a number into a cell in Excel, the number is divided by 100. This is because Excel stores numbers as "floating point" values, which means that they are stored as a number of digits to the left and right of a decimal point. When you enter a number into a cell, the number to the left of the decimal point is multiplied by 100 and the result is stored in the cell. For example, if you enter the number 1234 into a cell, the number 1234 is stored as the value 12.34.
The reason that numbers are divided by 100 when you enter them into Excel is because it makes it easier to work with large numbers. If you enter the number 1234 into a cell, and then multiply it by 100, you would get the result 12340. However, if you enter the number 12.34 into a cell and multiply it by 100, you would get the result 1234.0. As you can see, when working with large numbers, it is much easier to divide them by 100 when you first enter them into Excel.
There are some situations where you may not want your numbers to be divided by 100 when you enter them into Excel. For example, if you are entering currency values, you may want to keep the division by 100 so that your cells show two decimal places (e.g. $12.34). In this case, you can format your cells as "currency" before you enter your numbers.