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SAI International School

Grade-VII

Mathematics

CHAPTER-4: Simple Equations,

LESSON NOTE-5

SUBTOPICS: Recap

IMPORTANT POINTS DISCUSSED SO FAR:

1. An equation is a condition on a variable such that two expressions in the variable
should have equal value.

2. The value of the variable for which the equation is satisfied is called the solution of
the equation.

3. An equation remains the same if the LHS and the RHS are interchanged.

4. In case of the balanced equation, if we
(i) Add the same number to both the sides, or
(ii) Subtract the same number from both the sides, or
(iii) Multiply both sides by the same number, or
(iv) Divide both sides by the same number, the balance remains undisturbed, i.e., the
value of the

LHS remains equal to the value of the RHS

5. The above property gives a systematic method of solving an equation. We carry out
a series of identical mathematical operations on the two sides of the equation in such
a way that on one of the sides we get just the variable. The last step is the solution of
the equation.

6. Transposing means moving to the other side. Transposition of a number has the
same effect as adding same number to (or subtracting the same number from) both
sides of the equation.

When you transpose a number from one side of the equation to the other side, you
change its sign. For example, transposing +3 from the LHS to the
RHS in equation
x+ 3 = 8 gives
x= 8 – 3 (= 5).