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 any empty cell, type the following syntax: \=RAND() This function generates a random number between 0 and 10. The type of number it returns depends on the cell's format; for example, you'll get a number with two decimal places by default since that's Excel's standard number format.