# Basic Mathematics Concepts-Part 1

Basic Mathematics Concepts, Mathematics brings order to our lives and keeps chaos at bay.

## Basic Mathematics Concepts

1. The sum of the first eight odd numbers is?

The sum of first n odd numbers= n2

Hence n=8

Sum=8*8=64.

2. The smallest four-digit number divisible by 15 is

1) 1000

2) 1010

3) 1020

4) 1005

Smallest 4 digit number=1000

1000+(15-10)=10005

3. How many numbers between 101 and 300 are exactly divisible by both 3 and 5?

Answer:-Number of numbers divisible by 15

between 1 and 300=19

between 1 and 100=6

Required divisible numbers=19-6=3

4. If x+y=3 and x-y=1, then the value of xy is?

4xy=(x+y)2-(x-y)2

=32-12=9-1=8

xy=8/4=2

5. Find the sum of all natural numbers from 1 to 20.

1+2+3+4+….+20

x(x+1)/2=(20*21)/2

210

6. 4.48 is equal to ?

4.48=448/100

=112/25

=4*(12/15)

7. Find the sum of place and face values of 8 in 43836

Place value of 8 in 43836=800

Face value=8

sum=800+8=808

9. Find the unit’s digit in the sum of (245)205 + (141)205

Unit digit of (245)205 =5

Unit digit of (141)205 =1

sum=5+1=6

10. Which of the following is an imaginary number

1) -2,

2) sqrt(2)

3) sqrt(-3),

4) 1/3