Class 6 - Mathematics : Algebra
Exercise : 11.3
Top Block 1
NCERT Solutions Class 6 Mathematics Algebra
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.
(Hint: Three possible expressions are 5 + (8 – 7), 5 – (8 – 7), (5 x 8) + 7 make the other expressions)
Answer :
(a) (8 x 5) – 7
(b) (8 + 5) – 7
(c) (8 x 7) – 5
(d) (8 + 7) – 5
(e) 5 x (7 + 8)
(f) 5 + (7 x 8)
(g) 5 + (8 – 7)
(h) 5 – (7 + 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 + sp
Answer :
(c) and (d)
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
(b) 17y, y⁄17, 5z
(c) 2y + 17, 2y – 17
(d) 7m, –7m + 3, –7m – 3
Answer :
(a)z+1→ Addition
z–1→ Subtraction
y+17→ Addition
y–17→ Subtraction
(b) 17y→ Multiplication
y⁄17→ Division
5z→ Multiplication
(c) 2y+17→ Multiplication and Addition
2y–17→ Multiplication and Subtraction
(d) 7m→ Multiplication
–7m+3→ Multiplication and Addition
–7m–3→ Multiplication and Subtraction
Mddle block 1
Question: 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.
Answer :
(a) p+7
(b) p–7
(c) 7p
(d) p⁄7
(e) –m–7
(f) –5p
(g) –p⁄5
(h) –5p
Question: 5.Give expression 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 result is subtracted from 16.
(h)y is multiplied by –5 and the result is added to 16.
Answer :
(a) 2m + 11
(b) 2m – 11
(c) 5y + 3
(d) 5y – 3
(e) –8y
(f) –8y + 5
(g) 16 – 5y
(h) –5y + 16
Question: 7. (a) From 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.
Answer :
(a) t + 4, t – 4, 4 – t, 4t, t4, 4t
(b) 2y + 7, 2y – 7, 7y + 2, 7y – 2 and so on