Young students should understand that, when looking at a two-digit number, the left number represents “10’s”, and the right number represents “1’s.” This is a critical math skill needed for subsequent math advancement.
Here is a simple way to help your child practice this concept. First practice counting by tens, to 100, until your child can easily and fluently do it herself (10, 20, 30, etc.).
Then follow these steps:
- Take an 8 ½ x 11 inch paper and fold it, vertically, in the middle. You should have two equal columns. Trace the fold line, top to bottom, so the columns can clearly be seen.
- On the top of the left column, print the word “tens” using all lowercase letters.
- On top of the right column, print the word “ones.”
- Say the number 24 (as an example) to your child.
- With a pencil, make two thin vertical rectangles, about an inch long, to represent two tens, in the left-hand tens column.
- Make four small dots in the right-hand ones column, directly across from the two rectangles in the tens column.
- Count the vertical rectangles by tens and count the dots by one. Help your child count the number using the rectangles and dots. Start with the tens column and move across to the ones column. “Ten, twenty, then twenty-one, twenty-two, twenty-three, twenty-four.”
- After practicing a few different two-digit numbers together, say a two-digit number, and see if she can draw the rectangles and dots in the correct columns. Practice until she can easily show you the tens and ones in a two-digit number.
Knowing that two-digit numbers can be broken apart into tens and ones, then put back together, gives your child a deeper concept of how math operations work. Understanding place value goes beyond memorization and teaches the “why” of addition and subtraction.