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Toggle## NCERT Solution For Class 6, Maths, Chapter 11, Algebra, Exercise 11.3

## Exercise 11.3

**Q.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.**

**Ans: **Some of the expressions formed by 5, 7 and 8 are as follows:

(5 x 7) + 8

(5 x 7) – 8

(5 + 7) – 8

5 + (8 – 7)

(8 + 5) – 7

(8 + 7) – 5

5 + (8 x 7)

5 – (7 + 8)

5 – (7 x 8)

**Q.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**

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

**Q.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 **

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

**(c) 2y + 17, 2 y – 17 **

**(d) 7 m, – 7 m + 3, – 7 m – 3**

**Ans: ****(a) z +1, z – 1, y + 17, y – 17 **

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**

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, 2 y – 17 **

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 to the result (Multiplication and subtraction)

** ****(d) 7 m, – 7 m + 3, – 7 m – 3**

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 to the result (Multiplication and subtraction)

**Q.4. Give expressions for the following cases.**

**(a) 7 added to p (b) 7 subtracted from p**

**(c) p multiplied by 7 (d) p divided by 7**

**(e) 7 subtracted from – m (f) – p multiplied by 5**

**(g) – p divided by 5 (h) p multiplied by – 5**

**Ans: **(a) 7 added to p = p + 7

(b) 7 subtracted from p = p – 7

(c) p multiplied by 7 = 7p

(d) p divided by 7 = p/7

(e) 7 subtracted from – m = -m – 7

(f) – p multiplied by 5 = -p x 5 = -5p

(g) – p divided by 5 = -p/5

(h) p multiplied by – 5 = p x -5 = -5p

**Q.5. Give expressions in the following cases.**

**(a) 11 added to 2m **

**(b) 11 subtracted from 2m**

**(c) 5 times y to which 3 is added **

**(d) 5 times y from which 3 is subtracted**

**(e) y is multiplied by – 8**

**(f) y is multiplied by – 8 and then 5 is added to the result**

**(g) y is multiplied by 5 and the result is subtracted from 16**

**(h) y is multiplied by – 5 and the result is added to 16.**

**Ans: **(a) 11 added to 2m = (2m + 11)

(b) 11 subtracted from 2m = (2m – 11)

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

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

(e) y is multiplied by -8 = – 8y

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

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

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

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

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

**Ans: **(a)(t + 4), (t – 4), 4t, (t / 4), (4 / t), (4 – t), (4 + t) are the expressions using t and 4.

(b) 2y + 7, 2y -7, 7y + 2, 7y – 2 and so on.