Count to 100 by tens. Start with the hundreds chart, then gradually move away from it.
Where is skip-counting by 2s and 5s? These are easy because 10 is divisible by both 2 and 5. Should we teach skip counting by other numbers, 3, etc? Would doing so be helpful for repeated adding when learning to multiply? Can’t find it in the K-2 Common Core. Could certainly be done once adding within 100 is mastered. When I skip count by 7, I do so by adding in my head. Where is counting backwards? Once students have mastered the one less concept, they should be able to count backwards, slowly, by repeated subtraction. Eventually they will memorize the sequence.
Counting by tens by Khan Academy
Count tens by Khan Academy
Conclude by leading this investigation:
Speed Counting to Infinity
K.CC.A.1: Count to 100 by ones and by tens.