Count backwards by ones from 20.
Represent a number of objects with a written numeral.
Counting by 100s: 345, 445, 545,645, ...
Given a number from 1-20, count out that many objects.
Count to 100 by ones and by tens.
Answer the question "how many?" by counting up to 20 objects arranged in a line, a rectangular array, a circle, or as many as 10 objects in a scattered configuration.
Use one-to-one correspondence when counting objects.
Counting by 10s: 217, 227, 237, 257, ...
Count forward beginning from a given number within the known sequence (instead of having to begin at 1).