Addition and subtraction equations are the equations which contain addition or subtraction.

For example,

x + 5 = 7

y - 3 = 4

Let us see, how to solve equations which contain addition or subtraction.

**Example 1 :**

Solve for x : x + 7 = 8

**Solution :**

x + 7 = 8

Since we are trying to solve for "x", we have to get rid of 7 which is added to "x".

To get rid of 7, we have to take -7 on both sides.

aaaaaaaaaaaaaaaaaaaaaaax + 7 = 8 aaaaaaaaaaaaaaaaaaaaaaaaa- 7aa- 7 aaaaaaaaaaaaaaaaaaaaaa------------- aaaaaaaaaaaaaaaaaaaaaaax = 1 aaaaaaaaaaaaaaaaaaaaaa-------------

Hence, the value of "x" is 1.

**Example 2 :**

Solve for y : y - 3 = 2

**Solution :**

y - 3 = 2

Since we are trying to solve for "y", we have to get rid of 3 which is subtracted from "y".

To get rid of 3, we have to take +3 on both sides.

aaaaaaaaaaaaaaaaaaaaaay - 3 = 2 aaaaaaaaaaaaaaaaaaaaaaaa + 3 + 3 aaaaaaaaaaaaaaaaaaaaa----------------- aaaaaaaaaaaaaaaaaaaaaay = 5 aaaaaaaaaaaaaaaaaaaaa-----------------

Hence, the value of "y" is 5.

**Example 3 :**

When 7 is added to a number, we get 25. Find the number.

**Solution : **

Let "x' be the required number.

According to the question, we have

x + 7 = 25

Here "7" is added to "x". To get rid of 7, we have to subtract 7 on both sides and solve the equation as explained below.

(x + 7) - 7 = (25) - 7

x = 18

Hence, the required number is "18".

**Example 4 :**

John had some candies. He gave 5 candies to his friend and now he has 18 candies. How many candies did John initially have ?

**Solution : **

Let "m' be the no. of candies that John initially had.

According to the question, we have

m - 5 = 18

Here "5" is subtracted from "m". To get rid of 5, we have to add 5 on both sides and solve the equation as explained below.

(m - 5) + 5 = 18 + 5

m = 23

Hence, John initially had 23 candies.

**Example 5 :**

The sum of two numbers 22.5. If one number is 7.5, find the other number.

**Solution : **

Let "x' be the other number.

According to the question, we have

x + 7.5 = 22.5

Here "7.5" is added to "x". To get rid of 7.5, we have to subtract 7.5 on both sides and solve the equation as explained below.

(x + 7.5) - 7.5 = 22.5 - 7.5

x = 15

Hence, the other number is 15.

After having gone through the stuff given above, we hope that the students would have understood "Addition and subtraction equations".

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