Place Value Power

Every digit in a number has a job, and its job depends on where it sits. In the number 345, the 3 is not just a three - it sits in the hundreds place, so it means three hundred. The 4 sits in the tens place and means forty, and the 5 sits in the ones place and means five. Three hundred forty-five is really three hundreds, four tens, and five ones all working together.

Place value is why we can write any number with only ten digits. Move a digit one place to the left and it becomes ten times stronger. The 2 in 20 is ten times stronger than the 2 in 2. This trick is the secret behind our whole number system.

You can use place value to make big numbers friendly. To compare 412 and 389, just read from the left: both have hundreds, but four hundreds beats three hundreds, so 412 is greater - no counting needed.