I am struggling to teach my kiddos this concept. They are having a difficult time grasping it. How do you teach this?

Each day we put a straw in a 100's straw pocket chart, I don't know what it is called. We count the straws every day. On the 20th day, we count 10, 20. I also have a strip that has the numbers by 10's on it. We read the numbers. I have a teaching partner that has her children stand up to count. When they say 10, they hold out their right hand, 20 their left hand, 30 their right hand etc. I've had kinders struggle with this concept, but those are usually the ones who have trouble with number recognition.

I like counting by fives this way since there's five fingers on each hand. For tens, have kids sit in circle. Kids put both hands into circle and say next ten as go around circle.

Got that...I'd just start from a concrete, meaning base...counting by five fingers, counting by ten fingers fingers..after a bit, it becomes rote...but the meaning should underpin it...if they are just rattling off numbers, it's kind of like a two year old who can sing their abcs but not have any idea about letters. Counting by fives and tens implies that understanding of number.

We do the pocket chart as well. We count everyday to the number of the day (basically the number of days we've been in school so far). Then we also use our fingers. We show ten fingers, then have a partner add ten fingers. We have counted all the fingers in our classroom. We have also used linking cubes to count by tens. The students like it because they can count them if they need. My students who are struggling with counting by tens still are those that are struggling to count and recognize numbers. If a student cannot count beyond 50, it will be hard for them to count by 10s beyond 50. We also highlight our 100 chart with different colors for our 10s.