Selina Concise Class 6 Math Chapter 17 Fundamental Operations Exercise 17A Solution
EXERCISE 17A
(1) Fill in the blanks:
(i) 5 + 4 = 9 and 5 x + 4x = 9x
(ii) 12 + 18 = 30 and 12x2y + 18x2y = 30x2y
(iii) 7 + 16 = 23 and 7a + 16b = 7a + 16b
(iv) 1 + 3 = 4 and x2y + 3xy2 = x2y + 3xy2
(v) 7 – 4 = 3 and 7ab – 4ab = 3ab
(vi) 12 – 5 = 7 and 12x – 5y = 12x – 5y
(vii) 35 – 16 = 19 and 35ab – 16ba = 19ab
(viii) 28 – 13 = 15 and 28ax2 – 13a2x = 28ax2 – 13a2x
(2) Fill in the blanks:
(i) -2 + (- 5) = – 2 – 5 = – 7 and – 2x + (- 5x) = – 2x – 5x = – 7x
(ii) 8 + (- 3) = 8 – 3 = 5 and 8ab + (- 3ab) = 8ab – 3ab = 5ab
(iii) – 15 + (- 4) = – 15 – 4 = – 19 and – 15 x + (- 4y) = – 15 – 4y
(iv) 15 + 8 + 3 = 26 and 15x + 8y + 3x = 18x + 8y
(v) 12 – 9 + 15 = 3 + 15 = 18 and 12ab – 9ab + 15 ba = 3ab + 15ba = 18ab
(vi) 25 – 7 – 9 = 25 – 16 = 9 and 25xy – 7xy – 9yx = 9xy
(vii) – 4 – 6 – 5 = – 15 and – 4ax – 6ax – 5ay = – 10ax – 5ay
(3) Add:
(i) 8xy + 3xy = 11xy
(ii) 2xyx + xyz + 6xys = 9xyz
(iii) 2a + 3a + 4b = 5a + 4b
(iv) 3x+ 2y
(v) 5m + 3n + 4p
(vi) 6a + 3a + 9ab = 9a + 9ab
(vii) 3p + 4q + 9q = 3p + 13q
(viii) 5ab + 4ba + 6b = 9ab + 6b
(ix) 50pq + 30pq + 10pr = 80pq + 10pr
(x)- 2y + (- y) + (- 3y) = – 6y
(xi) – 3b + (- b) = – 4b
(xii) 5b + (- 4b) + (- 10b) = 5b – 14b = – 9b
(xiii) – 2c + ( – c) + (- 5c) = – 2c – c – 5c = – 8c
(4) Evaluate:
(i) 6a – a – 5a – 2a = 6a – 8a = – 2a
(ii) 2b – 3b – b + 4b = 6b – 4b = 2b
(iii) 3x – 2x – 4x + 7x = 10x – 6x = 4x
(iv) 5ab + 2ab – 6ab + ab = 6ab – 6ab = 0
(5) Evaluate:
(i) – 7x + 9x + 2x – 2x = 11x – 9x = 2x
(ii) 5ab – 2ab – 8ab + 6ab = 11ab – 10ab = ab
(iii) – 8a – 3a + 12a + 13a – 6a = 25a – 17a = 8a
(iv) 19abc – 11abc – 12abc + 14abc
= 33abc – 23abc = 10 abc
(6) Evaluate:
(7) Subtract the first term from the second:
(i) 6ba – 4ab = 2ab
(ii) 6.8b – 4.8b = 2b
(iii) 10.5abc – 3.5abc = 7abc
(8) Simplify:
(i) 2a2b2 + 5ab2 + 8a2b2 – 3ab2
= (2a2b2 + 8a2b2) + (5ab2 – 3ab2)
= 10a2b2 + 2ab2
(ii) 4a + 3b – 2a – b
= 4a – 2a + 3b – b
= 2a + 2b
(iii) 2xy + 4yz + 5xy + 3yz – 6xy
= 2xy + 5xy – 6xy + 4yz + 3yz
= 7xy – 6xy + 7yz
= xy + 7yz
(iv) ab + 15ab – 11ab – 2ab
= 16ab – 13ab
= 3ab
(v) 6a2 – 3b2 + 2a2 + 5b2 – 4a2
= 6a2 + 2a2 – 4a2 – 3b2 + 5b2
= 8a2 – 4a2 + 2b2
= 4a2 + 2b2
(vi) 8abc + 2ab – 4abc + ab
= 8abc – 4abc + 2ab + ab
= 4abc + 3ab
(vii) 9xyz + 15xyz – 10zyx – 2zyx
= 24xyz – 12 xyz
= 12xyz
(viii) 13pqr + 2p + 4q – 6pqr + 5pqr
= 13pqr + 5pqr – 6pqr + 2p + 4q
= 18pqr – 6pqr + 2p + 4q
= 12pqr + 2p + 4q
(ix) 4ab + 0 – 2ba
= 2ab
(x) 6x2y – 2xy2 + 5x2y – xy2
= 6x2y + 5x2y – 2xy2 – xy2
= 11x2y – 3xy2
(xi) 6.4a + 5.3b – 2.4a – 2.2b
= 6.4a – 2.4a + 5.3b – 2.2b
= 4a + 3.1b
(xii) 2.5a + 4.6b + 1.2a – 3.6b
= 2.5a + 1.2a + 4.6b – 3.6b
= 3.7a + b