math follow-up

38.8 - 29.9 =

The first thing you do if it is subtraction, you add 0.1 to the

 29.9 to make it a tidy number then you have to add 0.1 to 38.8

 because you added 0.1 to 29.9. So now it will look like this

 39.0 + 29.7 =

39.0 + 29.7 = 32.3. But if it’s addition you add 0.2 to the 38.8

and subtract 0.2 from the 29.9 so now it looks like this

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29.5 + 10.5=

(This one is similar to the first one)

This addition so we add to one and subtracted to 

the one. But you can’t just pick which one to add and 

which one to subtract First you add 0.5 to the 29.5 to

 make it 30.0. Then you subtract 0.5 from the 10.5 that = 10.0.

30.0 + 10.0 = 40.0