Understanding the Count Sequence to 120

Welcome to the exciting world of numbers! In first grade, we expand our counting skills all the way up to $120$. This means learning how to count forward, count backward, and easily find missing numbers using tools like the number line and the $120$ chart.

Counting Forward and Backward

Counting is just like taking steps.

• Counting Forward: Every time you say the next number, you are adding $1$. Example: $114, 115, 116, 117, 118, 119, 120$.
• Counting Backward: Every time you say the next number, you are taking away $1$. Example: $120, 119, 118, 117, 116, 115, 114$.

What Comes Before and After?

If you know the count sequence, you can easily tell what number comes right before or right after any given number.

• Before: The number that is exactly $1$ less. Question: What comes before $67$? Answer: $66$.
• After: The number that is exactly $1$ more. Question: What comes after $67$? Answer: $68$.

Using a 120 Chart

A $120$ chart is a grid that helps you see the patterns in numbers from $1$ all the way to $120$.

Here are the secret rules of the chart:

• Moving one square right adds $1$ (e.g., $45 \rightarrow 46$).
• Moving one square left subtracts $1$ (e.g., $45 \rightarrow 44$).
• Moving one square down adds $10$ (e.g., $45 \rightarrow 55$).
• Moving one square up subtracts $10$ (e.g., $45 \rightarrow 35$).

If you are asked to fill in a missing number on the chart, just look at its neighbors! If the number before it is $99$, the missing number must be $100$.