NCERT Solutions Class 6th Maths Chapter – 11 Algebra Exercise – 11.3

Question 1. Make up as many expressions with numbers (no variables) as you can from three numbers 5, 7 and 8. Every number should be used not more than once. Use only addition, subtraction and multiplication.

Solution: Some of the expressions formed by 5, 7 and 8 are as follows
5 × (8 – 7)
5 × (8 + 7)
(8 + 5) × 7
(8 – 5) × 7
(7 + 5) × 8
(7 – 5) × 8

Question 2. Which out of the following are expressions with numbers only?
(a) y + 3
(b) (7 × 20) – 8z
(c) 5(21 – 7) + 7 × 2
(d) 5
(e) 3x
(f) 5 – 5n
(g) (7 × 20) – (5 × 10) – 45 + p

Solution: (c) and (d) are the expressions with numbers only.

Question 3. Identify the operations (addition, subtraction, division, multiplication) in forming the following expressions and tell how the expressions have been formed.
(a) z + 1, z – 1, y + 17, y – 17

Solution:
z + 1 = 1 is added to z = Addition
z – 1 = 1 is subtracted from z = Subtraction
y + 17 = 17 is added to y = Addition
y – 17 = 17 is subtracted from y = Subtraction

(b) 17y, y / 17, 5z

Solution:
17y = y is multiplied by 17 = Multiplication
y / 17 = y is divided by 17 = Division
5z = z is multiplied by 5 = Multiplication

(c) 2y + 17, 2y – 17

Solution:
2y + 17 = y is multiplied by 2 and 17 is added to the result = Multiplication and addition
2y – 17 = y is multiplied by 2 and 17 is subtracted from the result = Multiplication and subtraction

(d) 7m, -7m + 3, -7m – 3

Solution:
7m = m is multiplied by 7 = multiplication
-7m + 3 = m is multiplied by -7 and 3 is added to the result = Multiplication and addition
-7m – 3 = m is multiplied by -7 and 3 is subtracted from the result = Multiplication and subtraction

Question 4. Give expressions for the following cases.

(a) 7 added to p
Solution: 7 is added to p is (p + 7)

(b) 7 subtracted from p
Solution: 7 subtracted from p is (p – 7)

(c) p multiplied by 7
Solution: p multiplied by 7 is (7p)

(d) p divided by 7
Solution: p divided by 7 is (p / 7)

(e) 7 subtracted from -m
Solution: 7 subtracted from –m is (-m – 7)

(j) -p multiplied by 5
Solution: –p multiplied by 5 is (-5p)

(g) -p divided by 5
Solution: –p divided by 5 is (–p / 5)

(h) p multiplied by -5
Solution: p multiplied by -5 is (-5p)

Question 5. Give expressions in the following cases.
(a).11 added to 2m
Solution: 2m + 11

(b) 11 subtracted from 2m
Solution: 2m – 11

(c) 5 times y to which 3 is added
Solution: 5y + 3

(d) 5 times y from which 3 is subtracted
Solution: 5y – 3

(e) y is multiplied by -8
Solution: -8y

(f) y is multiplied by -8 and then 5 is added to the result
Solution: -8y+5

(g) y is multiplied by 5 and the result is subtracted from 16
Solution: 16 – 5y

(h) y is multiplied by -5 and the result is added to 16.
Solution: -5y + 16

Question 6. (a) Form expressions using t and 4. Use not more than one number operation. Every expression must have t in it.

Solution: (t + 4), (t – 4), 4t, (t / 4), (4 / t), (4 – t), (4 + t) are the expressions using t and 4

(b) Form expressions using y, 2 and 7. Every expression must have y in it. Use only two number operations. These should, be different.

Solution: 2y + 7, 2y – 7, 7y + 2,… are the expression using y, 2 and 7