Learn Class 8 Math - Playing with Numbers

What is the General Form of Numbers?

For PQ, if the general form is needed, it will look like this:

pq=10p+q

Games with Numbers

Reversing the Digits – Two-Digit Number

Step 1: Let us select any two-digit number ab, which may be written as (10a + b).

Step 2: Its opposite two-digit number can be ba, which may be written as (10b + a).

Step 3: The sum of each of the numbers is ab + ba,

Step 4: By dividing the number by 11, we get eleven (a + b)/11 = (a + b).

Reversing the Digits – Three Digit Number

Step 1: Let's pick any 3 digit quantity ABC, which may be written as (100a + 10b + c).

Step 2: Its opposite quantity can be CBA, which may be written as (100c + 10b + a).

Step 3: By subtracting each of the numbers, i.e. ABC - CBA

Step 4: By dividing the quantity via 99 we get 99 (a-c)/9 = (a-c).

Forming Three-digit Numbers with three digits.

Step 1: Let us take any 3 digit quantity ABC, which may be written as (100a +10b + c).

Step 2: Rearrange the quantity in this type of manner that is bureaucracy specific numbers.

Step 3:By including all of the 3 numbers

Step 4:By dividing the quantity by 37, we usually get the rest zero.

Playing with Numbers Sample Questions for Class 8

Question 1

If x is an even number, then x4n, where n is a positive integer, will always have :
A. zero in the unit's place
B. 6 in the unit's place
C. either 0 or 6 in the unit's place
D. None of these

Question 2

is equal to:
A. 2
B. 4
C. 295
D. 643

Question 3

A positive integer, which when added to 1000, gives a sum which is greater than when it is multiplied by 1000. This positive integer is :
A. 1
B. 3
C. 5
D. 7

Question 4

9358 – 6014 + 3127 = ?
A. 6381
B. 6471
C. 6561
D. 6741

Question 5

Find the sum of prime numbers lying between 60 and 75
A. 199
B. 201
C. 211
D. 272