# Mathsight Class 7 Solutions Chapter 1

## Mathsight Class 7 Solutions Chapter 1 Knowing Our Numbers

Welcome to NCTB Solutions. Here with this post we are going to help 7th class students to solve MathSight Class 7 Mathematics Book, Chapter 1, Knowing Our Numbers. Here students can easily get all the exercise questions solution for Chapter 1, Knowing Our Numbers Exercise 1.1, 1.2 and 1.3

Knowing Our Numbers Exercise 1.1 Solution :

Question no – (1)

Solution :

(d) 4(3)

Question no – (2)

Solution :

(a) 23 × 13 = 299

(b) 0 × (-34) = 0

(c) 11 × (-17) = 187

(d) (-19) × 14 = 266

(e) (-6) × (-29) = 174

(f) -4 × (-1) × (-21) × 9 = -786

Question no – (3)

Solution :

(a) 10

(b) 0

(c) 2

(d) 0

Question no – (4)

Solution :

Coastline diminish 1 year = 4 cm

∴ Coastline diminish 6 year,

= 6 × 4

= 24 cm

∴ The integer = -24 cm

Question no – (5)

Solution :

1(-3) × 51 = (- 3 + 5) – (- 3 × 5)

= 2 – (-15)

= 2 + 15

= 17

Therefore the value will be 17.

Question no – (6)

Solution :

= 3 × (-17)

= -51

Question no – (7)

Solution :

No, not correct.

-7 and -17 both are negative integer. Product of two negative integer always well be positive.

∴ product correctly should be 119.

Question no – (8)

Solution :

(-4) × (-7) = 28

∴ 4 + (-7)

= – 4 – 7

= -11

Hence, the least possible sum of a and b will be -11.

Knowing Our Numbers Exercise 1.2 Solution :

Question no – (1)

Solution :

Correct option – (b)

The average temperature change par hour will be -2°C

Question no – (2)

Solution :

(a) 18 ÷ (-6)

= -3

∴ The quotient = -3

(b) (-33) ÷ 11

= -3

∴ The quotient = -3

(c) (-45) ÷ (-15)

= 3

∴ The quotient = 3

(d) 0 ÷ 13

= 0

∴ The quotient = 0

(e) 123 ÷ (-3)

= -41

∴ The quotient = -41

(f) (-62) ÷ (-31)

= 2

∴ The quotient = 2

(g) 34 ÷ 34

= 1

∴ The quotient = 1

(h) 95 ÷ (-19)

= -5

∴ The quotient = -5

Question no – (3)

Solution :

(a) -729 ÷ 9 = -81

(b) 45 ÷ (-9) + (-12) = – 17

(c) 23 ÷ (-23) + (2) = -3

(d) 0 ÷ (-12) – (-14) = -14

Question no – (4)

Solution :

(a) | 35 ÷ (-7) | = |-5|

(b) | (-152) ÷ (-19)| = |8|

(c) | (-144) ÷ 16| = |-9|

(d) | (-20) – (-15) ÷ 3 – (-2) | = |-1|

(e) | 12 × (-10) ÷ 5| =

(f) | 34 – 16 ÷ 8 – (-10) | = |42|

Question no – (5)

Solution :

Elevation change for 1 min,

= 10 ÷ 5

= 2 feet.

Question no – (6)

Solution :

(a) a ÷ b = 10 ÷ (-2)

= -5

(b) 10b² ÷ c

= 10 × (-2)² ÷ (-5)

= 40 ÷ (-5)

= -8

(c) -ab² ÷ (-c)

= [-{10 × (-2)²}] ÷ (-5)

= 40 ÷ 5

= 8

(d) (ac + a) ÷ b = (10  × (-5) + 10) ÷ (-2)

= (-50+10) ÷ (-2)

= -40 ÷ (-2)

= 20

Question no – (7)

Solution :

= (-80) ÷ 5

= -16

Question no – (8)

Solution :

-8, -4,

Knowing Our Numbers Exercise 1.3 Solution :

Question no – (1)

Solution :

(a) 13

(b) 0

(c) 11

(d) 2

(e) -6

(f) 4

(g) -5, -9

Question no – (2)

Solution :

(a) → (iv) → (vi) 12

(b) → (v) → (iv) -12

(c) → (vi) → (i) -8

(d) → (vii) → (ll) 0

(e) → (ii) → (vii) 1

(f) → (iii) → (iii) -2

(g) → (i) → (v) -51

Question no – (3)

Solution :

(a) → False

(b) → True

(c) → True

(d) → False

(e) → True

(f) → False

Question no – (4)

Solution :

(a) Using associate property of addition-

(-142) + (-58) + 200

L.H.S,

(-142-58) + 200

= – 200 + 200

= 0

R.H.S,

-142 + [-58 + 200]

= -142 + 142

= 0

(b) Using distribution property over addition .

134 × 11 + 134 × 9

= 134 × (11+9)

= 2680

(c) Using multifactional property

Question no – (5)

Solution :

(-34) ÷ (-1) = -34

Question no – (6)

Solution :

(a) (-14) × (-13)

= 21

(b) { 23 + (-17)} – 19

= -13

Question no – (7)

Solution :

(a) (-14) × (-13)

= 182

(b) (-11) × [23+(-10)]

= -143

Question no – (8)

Solution :

Elevation change 1 min,

= 1200 ÷ 4

= 300 feet .

Question no – (9)

Solution :

32/(-4) = – 8      [32, -40]

-40/5 = -8         [-40, 5]

-16/2 = -8         [-16, 2]

80/(-10) = -8    [80, -10]

56/(-7) = -8      [56, -7]

Question no – (10)

Solution :

The integer = 5 × 4 = 20

(a) out side food is not healthy for students.

(b) How cooked food is hygienic and healthy

Next Chapter Solutions :

Updated: May 27, 2023 — 9:37 am