CBSE Class 6 Maths - Playing With Numbers - NCERT Exercise 3.7 (#cbsenotes)

Playing With Numbers

EXERCISE 3.7

CBSE Class 6 Maths

Q1: Renu purchases two bags of fertiliser of weights 75 kg and 69 kg. Find the maximum value of weight which can measure the weight of the fertiliser exact number of times.

Answer: 
 The maximum weight  = HCF of 75 and 69.
 Factors of 75   = 3 ✕ 5 ✕ 5
 Factors of 69   = 3 ✕ 69
    HCF  = 3
 ∴ the required weight is 3 kg.

Q2: Three boys step off together from the same spot. Their steps measure 63 cm, 70 cm and 77 cm respectively. What is the minimum distance each should cover so that all can cover the distance in complete steps?

CBSE Class 7 Maths - Integers - NCERT Exercise 1.2 (#cbsenotes)

Integers

EXERCISE 1.2

CBSE Class 7 Maths

Q1: 1. Write down a pair of integers whose:
(a) sum is –7
(b) difference is –10
(c) sum is 0

Answer:
(a) One such pair whose sum is -7 = -4 + (-3) = -7
(b) One such pair whose difference is -10 = -3 - 7 = 10
(c) One such pair whose sum is 0 = -5 + 5 = 0

CBSE Class 9 - Unit Test Paper Hindi(हिंदी) Sample Question Paper (2017-18) (#cbsepapers)

CBSE Class 9 - Unit Test Paper Hindi (हिंदी) Sample Question Paper (2017-18)

CBSE Class 6 Maths - Playing With Numbers - NCERT Exercise 3.6 (#cbsenotes)

Playing With Numbers

EXERCISE 3.6

CBSE Class 6 Maths

Q1: Find the HCF of the following numbers:
(a) 18, 48
(b) 30, 42
(c) 18, 60
(d) 27, 63
(e) 36, 84
(f) 34, 102
(g) 70, 105, 175
(h) 91, 112, 49
(i) 18, 54, 81
(j) 12, 45, 75

Answer:

(a) Factors of 18 = 2 × 3 × 3
Factors of 48 = 2 × 2 × 2 × 2 × 3
HCF (18, 48) = 2 × 3 = 6

(b) Factors of 30 = 2 × 3 × 5
Factors of 42 = 2 × 3 × 7
HCF (30, 42) = 2 × 3 = 6

(c) Factors of 18 = 2 × 3 × 3
Factors of 60 = 2 × 2 × 3 × 5
HCF (18, 60) = 2 × 3 = 6

CBSE Class 10 - Biology - Digestive Organs and Their Functions (#cbsenotes)

Digestive Organs and Their Functions

CBSE Class 10 - Physics - Electricity - Important Points To Remember (#cbsenotes)

Electricity - Important Points To Remember 

CBSE Class 10 - Physics 

① Electric current is defined as the amount of charge flowing through a particular cross section area in a unit time.


② The SI unit of electric current is ampere.


③ A stream of electrons moving through a conductor constitutes an electric current. In a conventional current, the direction of current is taken opposite to the direction of flow of electrons i.e. flow of positive charges from +ve terminal to -ve terminal.


④ 1 A is the flow of 6.25 × 10¹⁸ electrons per second, or 1 coulomb per second.

CBSE Class 6 Maths - Playing With Numbers - NCERT Exercise 3.5 (#cbsenotes)

Playing With Numbers

EXERCISE 3.5

CBSE Class 6 Maths

Q1: Which of the following statements are true?
(a) If a number is divisible by 3, it must be divisible by 9.
(b) If a number is divisible by 9, it must be divisible by 3.
(c) A number is divisible by 18, if it is divisible by both 3 and 6.
(d) If a number is divisible by 9 and 10 both, then it must be divisible by 90.
(e) If two numbers are co-primes, at least one of them must be prime.
(f) All numbers which are divisible by 4 must also be divisible by 8.
(g) All numbers which are divisible by 8 must also be divisible by 4.
(h) If a number exactly divides two numbers separately, it must exactly divide their sum.
(i) If a number exactly divides the sum of two numbers, it must exactly divide the two numbers separately.


Answer:
(a) ✗ (e.g. 15 is divisible by 3 but not by 9)
(b) ✔
(c) ✔
(d) ✔
(e) ✗ (e.g. 8 and 9 are co-primes and none of these are prime. )
(f) ✗
(g) ✔
(h) ✔
(i) ✗


Q2: Here are two different factor trees for 60. Write the missing numbers.