Skip counting by 10s (10, 20, 30...) reveals the base-ten structure of our number system. Each number is 10 more than the previous, connecting directly to place value.
You already know how to count one at a time: 1, 2, 3, 4... all the way to 20 and beyond. Skip counting by 10s is a different kind of counting — instead of adding 1 each time, you jump forward by 10. The sequence looks like this: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100. You are skipping over nine numbers each time and landing on every tenth one.
One way to see this is on a number line. If you start at 10 and make jumps of 10, each jump lands you on a new "decade" number: twenty, thirty, forty. You can also picture it with objects: if you have groups of 10 blocks, skip counting tells you the total as you add one group at a time — 10 blocks, 20 blocks, 30 blocks. Each group you add gives you 10 more.
Here is a pattern worth noticing: every number you say when skip counting by 10s ends in a zero — 10, 20, 30, 40. The ones digit never changes; it stays at 0. Only the tens digit goes up: 1, 2, 3, 4... This is your first look at something very important called place value. In our number system, different positions (ones, tens, hundreds) each have their own digit. When you add 10, only the tens position changes, and the ones position stays the same.
This connects directly to what you will learn next about tens and ones. When you write the number 30, the 3 means "3 tens" and the 0 means "0 ones." Skip counting by 10s is really just counting by tens — one group of ten, two groups of ten, three groups of ten. Understanding this will make it much easier to work with bigger numbers later on.