3.005 plus 6.12 equals what?
To help us add these two numbers mentally, we can change the order in which we add. We start at 6.12 and add 3.005. The three digit in 3.005 represents three ones. 6.12 plus three is 9.12. We’ve just added three to the ones digit. There are no tenths to add and no hundredths to add. We just need to add five thousandths to 9.12, which takes us to 9.125.
We could also add these two numbers using column addition. We just have a five in the thousandths column. Two hundredths and no hundredths gives us a total of two hundredths. One tenth and no tenths give us a total of one tenth. We need to remember to write the decimal point. Then we can add the six and the three ones which makes nine. 3.005 plus 6.12 equals 9.125.