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.
Example 3: Count the number of cells in a range that do not contain text. In this example, the criterion must be wrapped in quotation marks since we are using an operator. We use the wildcard * to refer to any text. Excel counts the number of cells that do not contain text and returns a value of 1 (cell A4).xample 3: Count the number of cells in a range that do not contain text. In this example, the criterion must be wrapped in quotation marks since we are using an operator. We use the wildcard * to refer to any text. Excel counts the number of cells that do not contain text and returns a value of 1 (cell A4).