How can you know the place value of 0 in 2.30506?

Answer 1

It doesn't matter where the 0 is in the number, its place value is always 0.

However, to calculate the place value for any digit the decimal point tells you where to start the place value columns from.

To the left of the decimal point starting with the column immediately to the left of the decimal point the columns have place values: 1, 10, 1000, ... multiplying by 10 for each column left you go.

To the right of the decimal point, starting with the column immediately to the right of the decimal point, the columns have place values: 1/10, 1/100, 1/1000, ... dividing by 10 for each column right you go.

So starting with the column immediately to the left of the decimal point and a value of 1, multiply the value by 10 if you move left a column, or divide the value by 10 if you move right a column, move through the columns until you reach the digit. once you have reached you digit, you have found the value of its column and multiplying the two together will tell you the digits value.

Example: for the 5, starting to the left of the decimal point with 1, it is required to move right 3 columns, so divide by 10 three times to get the column value for the 5 of 1/1000 which, when multiplied by 5 gives its value as 5/1000 or five thousandths.