Question 1

What does algebra primarily introduce in mathematics?

Accepted Answer

Algebra introduces the idea of using letters or alphabets to represent unknown quantities, allowing us to write rules and formulas in a general way.

Question 2

If 'l' is the length of the side of a square, then the perimeter of the square is given by:

Accepted Answer

The perimeter of a square is the sum of all its four sides. Since all sides are equal to 'l', the perimeter is 4 × l = 4l.

Question 3

The side of a regular hexagon is denoted by 'l'. The perimeter of the hexagon is:

Accepted Answer

A regular hexagon has 6 equal sides. The perimeter is calculated by multiplying the number of sides by the length of one side, which gives 6l.

Question 4

Which of the following is an expression with numbers only?

Accepted Answer

An expression with numbers only consists exclusively of numbers and fundamental arithmetic operations without any variables. Therefore, 4 + 3 is the correct expression.

Question 5

What is the algebraic expression for 'The sum of x and 5'?

Accepted Answer

The word 'sum' indicates addition. Therefore, adding 5 to x gives the algebraic expression x + 5.

Algebra — NCERT Class 6 Mathematics Important Questions & Revision Notes