A mark for an empty place

You mean two hundreds, no tens and five ones. You write a 2, then a 5. That reads as 25. How can you show the empty tens column?

Rule: A zero holds a column. Remove it, and the number becomes a shorter number.

Without the 0, the 2 moves from hundreds to tens.

With no zeros, six numbers up to 9,999 all read as 25. They are 25, 205, 250, 2005, 2050 and 2500.

Try the lab to finish this lesson.