# Counting to 20 on a Number Line

Counting to 20 on a Number Line

• We will count each snake by saying the number as we count it and then crossing it off.
• We have ten snakes to begin with.
• Some more snakes appear and we will count on from ten to obtain a total.
• We have 11, 12, 13, 14, 15, 16, 17, 18 , 19 snakes.

• We will count the number of dogs by crossing off each dog as we say its number.
• We have twenty dogs.
• We move along our number line one place for every number that we count.

Supporting Lessons

# Counting Number to Twenty using a Number Line

We are going to count the number of dogs.

To do this we start at zero on the number line and move along one place for every dog that we count.

We can point at each dog and say the number as we count it.

We will then cross off each dog after we say the corresponding number so that we don’t count it twice. This can be more important with larger numbers and in our image below, the dogs are spaced out in no particular order.

We count ‘1’ and cross out a dog.

We count ‘2’ and cross out another dog.

We count ‘3’.

We count ‘4’.

We count ‘5’.

We continue to move along the number line.

…6, 7, 8…

We continue to cross of each dog as we count it.

…9, 10, 11…

…12, 13, 14…

…15, 16, 17…

…18, 19, 20.

We have now counted all of the dogs.

The last number that we say as we cross off our last dog is 20.

There are twenty dogs altogether.

In the next example, we will count the number of snakes.

We will count the following snakes by counting up on ones and crossing off each snake as we count it.

There are 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

There are ten snakes altogether.

Some more snakes appear. So, we start at 10 and count up in ones as we move along the number line. We will continue to cross off each snake as we count it.

We count ‘11’ and cross out a snake.

We count ‘12’ and cross out a snake.

We count ‘13’ and cross out another snake.

We continue to count up in ones, crossing off each snake as we count it.

…14, 15, 16…

…17, 18, 19…

We have crossed off all of the snakes. This means that we have counted all of them. There are nineteen snakes altogether.

Now try our lesson on Tens and Units Place Value Chart where we learn how to write two-digit numbers and group tens and units (ones).

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