Decimal point : The point in a decimal separating the digits representing multiples of wholes from the digits representing fractions of wholes.

Hundred : Hundred refers to the number 100.

Hundredth : Hundredth refers to the number $\frac{1}{100}=0.01=10^{-2}.$

Ten thousand : Ten thousand refers to the number $10,000=10^4.$

Ten thousandth : Ten thousandth refers to the number $\frac{1}{10,000}=0.0001=10^{-4}.$

Calculate $40\div 5$ and then put the decimal point in the right place taking into account that $0.0001 \div 0.01=\frac{1}{10000} \div \frac{1}{100}$ $=\frac{1}{100}=0.01$