Add and subtract positive and negative decimals

You would add and subtract them like a normal whole number, make sure to link up the decimals. You can use 0's as place holders if you need to. If you have two negatives your answer would be negative. When you subtract / add decimals just add them together. A positive plus a positive would be positive. If you have a positive plus a negative, subtract them and go with the sign of the greater number.

Ithink if im not mistaking b is -3 but im not a 100% sude

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