excel formula not returns to right value

Hello Guys

I have a problem with my Excel. I just recognize this error a few days ago

When I do the calculation by using the formula, the answer is not return to the right value. Please ref to below example

I made simple calculation

100+0.3 with simple formula and the answer is 100.3 ...when I paste as value the answer is 100.30
However when I do the reverse.. 100.30-100.00, the answer become 0.299999999999997. Why its not return to 0.3?


100.0000000000000000 0.3000000000000000
100.3000000000000000 0.2999999999999970