All mainstream credit card numbers obey a mathematical trick designed to catch the most common typos. It’s called the Luhn ...

Your card number is carefully structured. The very first digit is what’s known as the major industry identifier. A 4 means ...

Value Pak shows you the different ways to compare 2-digit numbers. (15m 44s) Add Tens and Ones Video has Closed CaptionsCC Join Mrs. Markavich for a word problem with her friend Professor Barble ...

Join Mrs. Markavich for a missing addend word problem with Professor Barble! Next look out for two of favorite Math Might friends D.C. and Value Pak as they help use learn to add two-digit number ...