[For benchmark 2.1]
Ordinal numbers should be used as often as possible by the teacher in his/her conversation during class. For example: "Let's count off every third person" or "Please sit in the first desk" or "On the number line, this is the first number, this is the second, etc."

[For benchmark 2.2]
Counting by 2's, 5's, and 10's can be introduced through the multiplication chart (sample follows). Have students work in small groups to fill in the chart (references may be used). Have students look for the patterns in the numbers and discuss these patterns with them. Help students to understand how the charts show counting by 2's, 3's, etc. Point out to students the importance of counting by 2's, 5's and 10's.

(Counting by 2's helps in counting objects faster, seeing if numbers are even which helps with division, reducing fractions. Counting by 5's helps in telling time and counting change. Counting by 10's helps in counting money, adding, etc.)