Decimal Numbers

[0.1 - one tenth] [0.01 - one hundredth] [0.001 - one thousandth]

Adding Regular decimals is basic math.

.39

+.79

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1.18

Just add the numbers as you regularly would like 39+79, but they're both 2 decimals away so 118 reduced two decimal places equals 1.18

Same with subtracting

.39

-.79

-------

-.40