Entering Fractions in a Spreadsheet

Entering fractions in a spreadsheet. When entering fractions in a spreadsheet, we have to be aware of the order of operations. If we have a fraction like 2/3 times four, and we just enter it straight two divide three times four, the result that shows up in the cell is 2.66 67, and that's not the answer you want. It's not that the computer has made an error, it's that it is doing the calculations in a particular order. This is called the order of operations, and most spreadsheets use an order called Pin DOS. PI DOS stands for parentheses, exponents, multiplication and division, and addition and subtraction. When evaluating our input, the spreadsheet does the calculations we've entered in this order. First, it evaluates everything inside the parentheses. Then it evaluates all the exponents. Then it does multiplication and division. Then it does addition and subtraction. When evaluating our input, the first thing the computer looks at is the two divide three. In the computer's brain, it evaluates that as 2/3, which is 0.666 dot dot dot. Repeating decimal that goes on forever. Then it looks at the times four and multiplies the 0.66 6666, on forever by four, which is 2.66 6666 on forever. The computer then rounds that up to 2.66 67 and puts that into the spreadsheet cell. However, what we want is to have the three times four evaluated first and then divide two by that result. Let's hit the backspace key and try again. The two and divide keys are fine. But we'll now put the three times four in parentheses. Inside the computer, it evaluates the three times four first, since it is in parentheses. Three times four is 12. The computer tugs that away in its memory for later and then it goes back and starting at the beginning, reads the two divide part. The computer pulls the 12 out of memory and divides two by 12. To divided by 12 is 0.16 66 dot dot dot. The computer rounds that up to 0.16 67 and puts that into the spreadsheet cell. That's the correct answer for 2/3 times four.