Counting Forward & Backward to 20 - First Grade Mathematics

Counting is like walking along a straight mathematical path: you can step forward to reach higher numbers, or you can turn around and step backward toward zero. In kindergarten, you practiced counting up to ten. Now in first grade, you will extend your path all the way to 20 and learn to move comfortably in both directions. Counting forward builds your foundation for addition, while counting backward prepares your brain for subtraction. In this chapter, you will explore the full sequence of numbers up to 20 and learn how to count starting from any number.

The Forward Counting Sequence to 20

Counting forward means saying numbers in order from least to greatest, adding one unit with every step.

The Number Path from 1 to 20:
| 1| 2| 3| 4| 5| 6| 7| 8| 9|10|11|12|13|14|15|16|17|18|19|20|
 ----> Walking Forward: Each step adds 1 (+1) ---->

Crossing the Bridge from 10 to 11

Many mathematicians pause slightly when reaching ten. Remember that ten is the gateway: after 10 comes 11, then 12, 13, 14, 15, 16, 17, 18, 19, and finally 20. Twenty is two complete groups of ten.

Chanting with Rhythm

Practice chanting the numbers aloud with a steady beat: "1, 2, 3, 4, 5... 6, 7, 8, 9, 10... 11, 12, 13, 14, 15... 16, 17, 18, 19, 20!" Clapping your hands or tapping your feet on each count helps lock the sequence in your memory.

Counting Backward from 20 to 0

Counting backward means saying numbers in reverse order, taking away one unit with every step.

Counting Backward from 20:
<---- Walking Backward: Each step subtracts 1 (-1) <----
20 -> 19 -> 18 -> 17 -> 16 -> 15 -> 14 -> 13 -> 12 -> 11 ->
10 ->  9 ->  8 ->  7 ->  6 ->  5 ->  4 ->  3 ->  2 ->  1 -> 0

The Blast-Off Countdown

Think of counting backward like a rocket ship countdown. When you count down from 10 to 0 (10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, blast off!), your voice counts down smoothly. You can do the exact same countdown starting all the way from 20!

The Turn-Around at 10

When walking backward through the teens, pay close attention to 13, 12, 11, and 10. After 11, the very next number going backward is 10, followed by 9. Practicing this shift ensures you do not get stuck when crossing from teen numbers back into single digits.

Counting On from Any Number

You do not always have to start counting at 1. Skilled mathematicians can begin at any number and keep counting forward.

Starting at 8 and Counting Forward 5 Steps:
Start: [8] -> Step 1: [9] -> Step 2: [10] -> Step 3: [11] -> Step 4: [12] -> Step 5: [13]
Landed on: 13!

The "Lock It in Your Head" Technique

If you are asked to start counting at 12, say "12" out loud, tap your forehead to "lock it in your head," and then count forward: "13, 14, 15, 16, 17." This technique saves time because you do not have to recount from 1 every time you solve a problem.

Practice Exercises

Exercise 1: Fill in the missing numbers in this forward counting sequence: 11, 12, , 14, , 16, 17, __, 19, 20.

Exercise 2: Count backward from 15 down to 9. Write each number in order as you say it.

Exercise 3: Start at the number 7 and count forward 6 steps. What number do you land on?

Exercise 4: What number comes right before 20 when counting forward, and what number comes right after 20?

Solutions and Explanations

Solution to Exercise 1: The missing numbers are 13, 15, and 18. The complete sequence is 11, 12, 13, 14, 15, 16, 17, 18, 19, 20.

Solution to Exercise 2: Counting backward from 15 to 9 gives: 15, 14, 13, 12, 11, 10, 9.

Solution to Exercise 3: Starting at 7 and counting forward 6 steps: step 1 is 8, step 2 is 9, step 3 is 10, step 4 is 11, step 5 is 12, and step 6 is 13. You land on 13.

Solution to Exercise 4: The number that comes right before 20 is 19. The number that comes right after 20 is 21.