Algebra-Solutions Ex-11.3

CBSE Class –VI Mathematics
NCERT Solutions
Chaper 11 Algebra (Ex. 11.3)

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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$y+3$

(b) (7×20)−8z$\left(7\times 20\right)-8z$

(c) 5(21−7)+7×2$5\left(21-7\right)+7\times 2$

(d) 5$5$

(e) 3x$3x$

(f) 5−5n$5-5n$

(g) (7×20)−(5×10)−45+p$\left(7\times 20\right)-\left(5\times 10\right)-45+p$

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$z+1,z-1,y+17,y-17$

(b) 17y,y17,5z$17y,\frac{y}{17},5z$

(c) 2y+17,2y−17$2y+17,2y-17$

(d) 7m,−7m+3,−7m−3$7m,-7m+3,-7m-3$

Answer:

(a) z+1→$z+1\to$ Addition

z−1→$z-1\to$ Subtraction

y+17→$y+17\to$ Addition

y−17→$y-17\to$ Subtraction

(b) 17y→$17y\to$ Multiplication

y17→$\frac{y}{17}\to$ Division

5z→$5z\to$ Multiplication

(c) 2y+17→$2y+17\to$ Multiplication and Addition

2y−17→$2y-17\to$ Multiplication and Subtraction

(d) 7m→$7m\to$ Multiplication

−7m+3→$-7m+3\to$ Multiplication and Addition

−7m−3→$-7m-3\to$ Multiplication and Subtraction

Question 4. Give expressions for the following cases:

(a) 7 added to p.$p.$

(b) 7 subtracted from p.$p.$

(c) p$p$ multiplied by 7.

(d) p$p$ divided by 7.

(e) 7 subtracted from −m.$-m.$

(f) −p$-p$ multiplied by 5.

(g) −p$-p$ divided by 5.

(h) p$p$ multiplied by −5.$-5.$

Answer:

(a) p+7$p+7$

(b) p−7$p-7$

(c) 7p$7p$

(d) p7$\frac{p}{7}$

(e) −m−7$-m-7$

(f) −5p$-5p$

(g) −p5$\frac{-p}{5}$

(h) −5p$-5p$

Question 5. Give expression in the following cases:

(a)11 added to 2m.$2m.$

(b)11 subtracted from 2m.$2m.$

(c) 5 times y$y$ to which 3 is added.

(d) 5 times y$y$ from which 3 is subtracted.

(e) y$y$ is multiplied by −8.$-8.$

(f) y$y$ is multiplied by −8$-8$ and then 5 is added to the result.

(g) y$y$ is multiplied by 5 and result is subtracted from 16.

(h) y$y$ is multiplied by −5$-5$ and the result is added to 16.

Answer:

(a) 2m+11$2m+11$

(b) 2m−11$2m-11$

(c) 5y+3$5y+3$

(d) 5y−3$5y-3$

(e) −8y$-8y$

(f) −8y+5$-8y+5$

(g) 16−5y$16-5y$

(h) −5y+16$-5y+16$

Question 7. (a) From expressions using t$t$ and 4. Use not more than one number operation. Every expression must have t$t$ in it.

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

Answer:

(a) t+4,t−4,4−t,4t,t4,4t$t+4,t-4,4-t,4t,\frac{t}{4},\frac{4}{t}$

(b) 2y+7,2y−7,7y+2,7y−2$2y+7,2y-7,7y+2,7y-2$ and so on