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.
As we all known, a prime number is a natural number which contains only two distinct natural number divisors: One and itself. If you have a list of numbers in a worksheet, how could you check if the numbers are prime numbers? Check if a number is prime number with array formula. Check if a number is prime number with User Defined Function. The following User Defined Function also can help you to check the numbers if prime or not, please do as follows: 1. Hold down the ALT + F11 keys to open the Microsoft Visual Basic for Applications window.