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1st Grade · 1.NBT.A.1

Counting to 120 in 1st grade

Counting to 120 means saying the numbers in order up to 120, starting from any number, not only from 1. In 1st grade, your child also learns to read and write every number up to 120. Your child counts a group of objects and writes the number that tells how many there are.

What the standard says

The official Common Core wording, quoted exactly. The plain version follows.

1.NBT.A.1 Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.

What it means, in plain words

In kindergarten, children count to 100, usually from 1. Counting to 120 in 1st grade goes 20 numbers further, and the count can start anywhere. Counting on means starting from a number in the middle, such as 46, and saying the numbers that come next: 47, 48, 49.

The hard spots are the turns, where the first digit goes up: 39 to 40, 89 to 90 and 99 to 100. After 100 the pattern starts again with a 1 in front: 101, 102 and so on up to 120. A number chart to 120 shows this well. Each row holds ten numbers, so the numbers in one column all end in the same digit.

Your child also reads and writes these numbers and matches a number to a group of things. If a jar holds 34 buttons, your child counts them and writes 34. Writing numbers past 100 is harder than saying them, because the spoken name gives no clue about where the digits go.

Your child should be able to:

  • Count forward by ones from any number up to 120
  • Say the number that comes after 39, 79 or 99 without starting over
  • Read and write any number from 0 to 120
  • Count a group of objects and write how many there are

Example

Count on by ones from 97. What are the next five numbers?

  1. Start at 97. The next number is 98, then 99.
  2. After 99 comes 100, the first number with three digits.
  3. Then the count goes on with 101 and 102.
  4. The next five numbers are 98, 99, 100, 101 and 102.

Example

How do you write the number one hundred seventeen?

  1. "One hundred" tells you the number starts with a 1.
  2. "Seventeen" is written 17.
  3. Put the 1 and the 17 side by side, with no zeros in between.
  4. One hundred seventeen is written 117.

Where children usually get stuck

  • Your child counts 37, 38, 39 and then says "thirty-ten" or jumps back to 30.

    Each new ten has its own name, like forty or fifty, and nothing in "thirty-nine" tells the child what comes next. The child knows the order inside each ten but not the word that starts the next one.

    What helps. Practice only the turns for a minute: you say 29, your child says 30. Then try 49, 69 and 89.

  • Asked to write one hundred eight, your child writes 1008.

    The child writes exactly what the words say: 100, then 8. Nobody has shown yet that the 8 goes in the place of the last zero.

    What helps. Write 100 on paper and cover the last 0 with a small card that says 8. Read the new number together: one hundred eight.

  • Your child counts from 1 to 120 with no trouble but gets stuck when asked to start at 64.

    Counting from 1 can be a chant learned like a song. Starting in the middle needs the child to know where each number sits, not only the order of the words.

    What helps. In the car or at dinner, take turns counting on: you say 64, your child says 65, you say 66. Change the starting number each time.

Try four practice questions

Real 1st grade questions from our question bank, easiest first. Answer them right here, check each one, and see a worked solution for any question.

  1. 1Warm-up
    Aiyana counted by ones, but one number is wrong: 8, 9, 1, 11. Which number does not belong?
    A
    8
    B
    9
    C
    1
    D
    11
    Show the answer and how to solve it

    1 does not belong. Counting by ones from 9 gives 10, not 1.

    1. 1Aiyana wrote four numbers in a row: 8, 9, 1, 11. When you count by ones, each number is 1 more than the one before it.
    2. 2Check each step. From 8 to 9 is 1 more — that fits the by-ones rule. From 9 to the next number, you should add 1: 9+1=109 + 1 = 10. But Aiyana wrote 1, not 10. That step does not add 1.
    3. 3After 10 comes 11(10+1=11)11 (10 + 1 = 11), and Aiyana did write 11 in the last spot — so the count picks up correctly after the slip. The one number that broke the by-ones pattern is 1 — it should have been 10.

    Common mistake. A common mistake is going back to the start of the same group of ten after a number ending in 9. After 9, the next number is 10, not 1.

    The idea underneath. Counting by ones means every step adds 1. To find a wrong number in a count, check each pair: is the next number exactly 1 more than the one before?

  2. 2On level
    Look at the meadow. How many butterflies do you see?
    Number of butterflies:
    Show the answer and how to solve it

    Answer. 11

    There are 11 butterflies in the meadow.

    1. 1Look at the meadow. There are butterflies scattered all around. To count them, touch each one as you say a number out loud.
    2. 2Count in groups of 5 to keep track. The first 5 butterflies make a group. The next 5 butterflies make another group, so now you have 10. Then count the last 1 butterfly one at a time: 11.
    3. 3The total is 11 butterflies.

    Common mistake. A common mistake is counting the same butterfly twice or skipping a butterfly when the butterflies are scattered. Touching each butterfly as you count helps keep track.

    The idea underneath. When you count a big group of objects, it helps to count in groups of 5 so you do not lose your place.

  3. 3On level
    Count by 1s starting at 20. What three numbers come next?
    A
    21, 22, 24
    B
    21, 22, 23
    C
    19, 18, 17
    D
    22, 24, 26
    Show the answer and how to solve it

    The next three numbers after 20 are 21, 22, 23. Each one is just 1 more than the number before it.

    1. 1We start at 20. The word 'next' means the numbers that come AFTER 20, not 20 itself.
    2. 2Counting by 1s means we add 1 each time. So the first next number is 21.
    3. 3Add 1 again to get 22. Add 1 one more time to get 23.
    4. 4The next three numbers are 21, 22, 23.

    Common mistake. A common mistake is starting the count at 20 itself and writing 20, 21, 22. The word 'next' means we begin one more than the starting number.

    The idea underneath. When you count by 1s, each next number is exactly 1 more than the one before it.

  4. 4Stretch
    The three ten-frames make a number. What number is it?
    A
    12
    B
    11
    C
    21
    D
    22
    Show the answer and how to solve it

    The number shown is 21. The first two ten-frames are full (10 each), and the third has 1 counter. Together, 10 and 10 and 1 more is 21.

    1. 1Look at the ten-frames. The first two ten-frames are completely full.
    2. 2Each full ten-frame shows 10. That gives us 10 and 10. The third ten-frame has 1 counter.
    3. 3Put them together. 10 and 10 and 1 more is 21.

    Common mistake. A common mistake is switching the digits and writing 12 instead of 21. The two full ten-frames count as 2 tens — the tens digit always comes first when you write the number.

    The idea underneath. A teen number is one ten plus some ones. A full ten-frame is always 10, so you just count the extra counters in the next frame to find the total.