Question

Without adding find the sum of 21+23+........+43+45​

Answer 1

Answer:

429

Step-by-step explanation:

n/2(a+l)

n=(l-a/d)+1

n=13

13/2(21+45)=sum of 21+23+......+43+45

13×33=429

Answer 2

Heya

Given Question - 21+23+25+27+29+31+33+35+37+39+41+43

(....) this means 21 to till 45..

Formula=number^2

We can calculate the number of odd numbers and we can also calculate the number of odd numbers by formula = n+1/2

Here n refers to the last odd digit number in the question..

Last odd number = 45

According to Formula =45+1/2

=46/2=23 .

Therefore total odd digits from 21 to 45 is 23..

Now Use formula n^2

= 23^2=529..

Therefore without adding the sum of21+23+25+27+29+31+33+35+37+39+41+43+45.

Dear saurav, if it helped you mark it as BRAINLIEST

=529.