It is hard to tell you exactly one person who invented decimals. Since decimals were an idea that went through many notational changes and usage. In the 1500's uslarchers and mathematicims were using some form of decimals, but not until Simon Stevin of Burged were they brought to the common people. He would soon write the power of ten assumed to be a divison after or above the digit of the decimal.
Decimals are very good for many reasons. They are easy to add. They make it easy to see how big a number is. In conclusion, can you think of two ways why we decimals.
This way of counting is old. Indo- European are spoken from India to
Europe and have the same counting system and very similar number and words.
We can conclude that the basic Indo European mother language had the same
method of counting (3000B.C.). Remember that no decimal number-system spoken
words like twenty three belong to the decimal counting system, 23 belongs
to the decimal number notation.