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.
Now, the user can type the table name into cell C6 and the SUM function will return the total of all cells in the table. If we want to allow the user to select a table name from a list of tables, we can use the data validation feature to provide a drop-down.