 Kids, don't you know that if you already know how to count from 1 until 10, you can easily count big numbers by grouping the objects by 10. Let's try that with numbers 21 until 30. If you have a set of 10 and another set of 10, that's 20. So 20 plus 1 equals 21. 20 plus 2 is 22. 20 plus 3 is 23. 20 plus 4 equals 24. 20 plus 5 equals 25. 20 plus 6 is 26. 20 plus 7 equals 27. 20 plus 8 equals 28. 20 plus 9 equals 29. And 20 plus another 10 equals 30. See, all you have to do is add the extra ones. Now, can you tell me what number is this? Right, 23. 21, yes. 24, correct. 28, yes. 26, correct. 30, right. Now kids, try to count the sets with 21 to 30 objects in your book now. That's all for today. Thanks for watching.