Simple Addition and Subtraction

Addition exercise - marked with +

We add something to a certain amount

For example:
Ed has $5$ candies and she received another $2$ candies from her friend Julia.
How many candies does Ed have now?

Solution:
We need to add $5+2=$
If we add $1$ to $5$ we get $6$
If we add another $1$ we get $7$ .
Therefore $5+2=0$

Subtraction operation - marked with -

We subtract something from a certain amount

For example:
Talia has $8$ candies and she gave her friend Ted $4$ candies.
How many candies does Talia have now?

Solution:
We need to subtract $8-4=$
If we subtract $1$ we get 7
If we subtract another $1$ we get $6$
If we subtract another $1$ we get $5$
If we subtract another $1$ we get $4$

Therefore $8-4=4$

Addition exercises

Example:
Gal has 12 shirts in the closet. Gal's mom bought her 3 more shirts.
How many shirts does Gal have now after her mom bought her more shirts?

Solution:
We need to add $12+3=$
Add $1$ we get $13$
Add another $1$ we get $14$
Add another $1$ we get $15$
Therefore $12+3=15$

Now we will solve addition exercises using vertical addition - ones under ones and tens under tens.

For example:

Noah has $12$ hair clips.
Noah's sister brought her $13$ more hair clips as a birthday gift because she knows she really likes them.
How many hair clips does Noah have now?

Solution:
Let's write the exercise in long addition:

A vertical addition problem with the numbers 12 and 13. The result is displayed below the line as 25.

Let's add ones with ones and get $5$
Let's add tens with tens and get $2$

We got that:
$12+13=25$
Wonderful!

Another exercise –
In class 2-1 there are $25$ students and in class 2-2 there are $24$ students.
How many students are there in total in both classes?

Solution:
We need to add $25+24=$
Let's write the exercise vertically with ones under ones and tens under tens and we get:

A vertical addition problem with the numbers 25 and 24. The result is displayed below the line as 49.

Let's add $5$ and $4$ we get $9$
Let's add $2$ and $2$ we get $4$

Total $49$

Click here to read more about vertical addition!

Subtraction Exercises

Example:
Guy has $14$ shirts in his closet. Guy's dog tore $3$ shirts and because of that he had to throw them in the trash.
How many shirts does Guy have now after throwing away the torn shirts?

Solution:
We need to subtract $14-3=$
Subtract $1$ we get $13$
Subtract another $1$ we get $12$
Subtract another $1$ we get $11$
Therefore $14-3=11$

Now we will calculate subtraction exercises using vertical subtraction - ones under ones and tens under tens.

Example:
Joan has $17$ hair clips.
Joan's sister took $5$ clips from her.
How many hair clips does Joan have now?

Solution:
Let's write the problem as a long subtraction:

A vertical subtraction problem with the numbers 17 and 5. The result is displayed below the line as 12.

We'll subtract ones from ones and get $2$
We'll add tens with tens and get $0$

We got that:
$17-5=2$
Wonderful!

Another exercise -
In class 2A there are $25$ students.
$12$ students went on a fun day at the beach and the rest stayed to study in class.
How many students stayed to study in class?