Updated By SaraNextGen

On March 11, 2024, 11:35 AM

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 × 8) + 7;

make the other expressions.)

Answer:

Many expressions can be formed by using the three numbers 5, 7, and 8.

Some of these 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

Answer:

It can be observed that the expressions in alternatives (c) and (d) are formed by using 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 (b) 

(c) 2y + 17, 2y − 17 (d) 7m, − 7m + 3, − 7m − 3

Answer:

(a) Addition as 1 is added to z.

Subtraction as 1 is subtracted from z.

Addition as 17 is added to y.

Subtraction as 17 is subtracted from y.

(b) Multiplication as y is multiplied with 17.

Division as y is divided by 17.

Multiplication as z is multiplied with 5.

(c) Multiplication and addition

y is multiplied with 2, and 17 is added to the result.

Multiplication and subtraction

y is multiplied with 2, and 17 is subtracted from the result.

(d) Multiplication as m is multiplied with 7.

Multiplication and addition as m is multiplied with −7, and 3 is added

to the result.

Multiplication and subtractionas m is multiplied by −7, and 3 is

subtracted from the result.

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) 

(e) − m − 7

(f) − 5p

(g) 

(h) − 5p

Question 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

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 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.

Answer:

(a) t + 4, t − 4, 4t,  ,  , 4 − t, 4 + t

(b) 2y + 7, 2y − 7, 7y + 2,…