What your child learns
- Count to 120 by ones, starting at any number, not just 1.
- Read and write numerals up to 120.
- Count forward and backward across tricky spots like 99 → 100 and 109 → 110.
- Count by tens from a decade (10, 20, 30) and from any number (4, 14, 24).
Common Core 1.NBT.A.1
By 1st grade most children can recite numbers to 20 or even 100, but counting on from a number like 87, or writing "one hundred four" correctly, is a new challenge. A 120 chart, a grid with 10 numbers in each row, is the best tool for this, because it makes the number pattern visible.
The pattern on a 120 chart
Each row on the chart starts with a number ending in 1 (1, 11, 21 and so on) and ends with a multiple of 10. Moving right adds 1. Moving down adds 10. Once children see that the ones digits repeat 0 to 9 in every row, they can count across any decade.
Example 1: Count on from 96 to 104
- Start at 96 and say: 97, 98, 99.
- After 99 comes the next hundred: 100.
- Keep the ones pattern going: 101, 102, 103, 104.
The tricky step is 99 to 100. Point to the chart: 99 is at the end of a row, and 100 starts the next one.
Example 2: Write "one hundred seven"
- "One hundred" means a 1 in the hundreds place.
- There are no tens, so write 0 in the tens place.
- Seven ones go in the ones place: 107.
A common mistake is writing 1007 ("100" and then "7"). Ask: "How many digits does a number in the hundreds have?" The answer is three.
Counting by tens from any number
Example 3: Count by tens from 6
6, 16, 26, 36, 46, 56, 66, 76, 86, 96, 106, 116
On the chart, this is moving straight down one column. The ones digit (6) never changes, and only the tens go up.
Practice
- Count on from 47 to 53. Write the numbers.
- What number comes after 109?
- What number comes before 100?
- Write the number "one hundred twelve".
- Count by tens from 30 to 120.
- Count by tens from 9. Write the next 5 numbers.
- Fill in the missing numbers: 114, 115, ___, ___, 118.
- Count backward from 105 to 98.
Show answers
- 47, 48, 49, 50, 51, 52, 53
- 110
- 99
- 112
- 30, 40, 50, 60, 70, 80, 90, 100, 110, 120
- 19, 29, 39, 49, 59
- 116, 117
- 105, 104, 103, 102, 101, 100, 99, 98
Common mistakes and quick fixes
- Getting stuck at the end of a decade (39 → "thirty-ten"): practice only the "row jumps" for a few minutes: 29, 30; 39, 40; 49, 50.
- Writing 100-something numbers with too many zeros (1004 for 104): build the number with place-value cards, then remove the cards and write it.
- Reversing teen numbers (writing 71 for 17): say the number slowly. "Seven-teen" has 1 ten and 7 ones, so the 1 is written first.
Try it at home
Make a 120 chart treasure hunt. Print or draw a 120 chart, hide small stickers on a few numbers, and give clues like "Start at 64, go down 3 rows", "Count on 5 from 99" or "The number after 109". Your child follows each clue to find the sticker.
This guide matches Unit 1: Counting to 120 in Level Up Math, Grade 1 (coming January 2027). Practice counting with the Count by Tens video lesson, or browse all K–2 lessons.
Questions parents ask
Why 120 and not 100?
Counting past 100 shows children that the pattern of tens and ones keeps going: 101, 102 and so on work just like 1, 2 and so on. The 1st grade standard (1.NBT.A.1) asks children to count to 120 starting at any number.
My child says 'one hundred and ten' as 'one hundred one zero'. How do I help?
Read the number in two parts: say 'one hundred', then read the rest as a normal two-digit number, 'ten'. Practicing with a 120 chart helps children see the pattern.
Should my child count by ones or by tens to get to 120?
Both. Counting by ones builds accuracy, and counting by tens builds place value and speed. Children who can count by tens from any number, like 7, 17, 27, are ready for 2nd grade addition.
