About 2

Point and name

One, two, three. Pointing at one thing at a time.

Subitising — seeing that a group is two without counting it — and the idea that a number word belongs to a thing you are touching.

About 4

Count and compare

Counting a real group to ten or twenty, and saying which is more.

One-to-one correspondence: one number word per object, the last word you said is how many there were. Then more, fewer, and the same.

About 6

Tally and figure

Tally marks, counting in twos and fives, and taking one number from another.

Grouping as a way of counting past what fingers hold, and subtraction as the distance between two numbers rather than a taking-away.