What is the estimate of the sum of 14.30 143.08 and 19.74?

Well, the idea is to round each number, then add them. This basically allows you to do estimated calculations in your head, whereas the complete operation would require (for most people) to use pencil and paper, or a calculator.

Since there are different ways to round numbers, the answers may vary. I would suggest, in this case, to round each number to the nearest multiple of 10.