The American Optometric Association suggests that children should have their first regular eye exam at six months of age. Another vision exam should take place when a child is around two or three years of age when their vision undergoes its most rapid development and vision correction is most effective.
The ISNUMBER function is a quick, easy way to check if a cell contains a number. Our example used the IF function to illustrate how ISNUMBER can be used. If you haven't used IF in a formula before, you can read our lesson on the IF function here.
My SUM function shows a whole number, but it should show decimals Check your cell formatting to make sure that you're displaying decimals. Select the cell or range in question and use Ctrl+1 to bring up the Format Cells dialog, then click the Number tab and select the format you want, making sure to indicate the number of decimal places you want.