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**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 : **

Chapter 2 | Chapter 3 | Chapter 4 | Chapter 5 | Chapter 6 |

Chapter 7 | Chapter 8 | Chapter 9 | Chapter 10 | Chapter 11 |

Chapter 12 | Chapter 13 | Chapter 14 | Chapter 15 |