120 chart

Why 120 and not 100

Stopping at 100 leaves a child thinking 100 is the end of something. The two extra rows show that the pattern simply continues: 101 sits under 91 the way 91 sits under 81, and 110 and 120 end their rows like every ten before them. That is the point of the standard, and it is why a 1st grade classroom chart usually runs to 120.

The layout is the same as the hundreds chart, so a child moving between the two does not have to relearn where anything is.

Using it in 1st grade

Start counting from a number in the middle of the chart rather than from 1, which is a specific skill in the standard. Cover the last two rows and ask what comes after 100 before uncovering them. Shade the tens and count down the right column past 100 to hear that the rhythm does not change. When the child can write the numbers 101 to 120 in order without the chart, the missing-numbers version of the hundreds chart makes a good check.