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.
In Excel, how do I check if a cell is in a list of values (a range of cells) I've got a range (A3:A10) that contains names, and I'd like to check if the contents of another cell (D1) matches one of the names in my list.