Arithmetic Prog...

Find the sum of the first $$15$$ positive odd numbers.

Find the sum of first 32 terms of the arithmetic series if $$a_1 = 12$$ and $$a_{32} = 40$$.

Given $$d=5, S_9=75$$, find a 

Find the sum of first 20 even terms of the arithmetic sequence.

Find the sum of first 10 terms of the arithmetic series if $$a_1 = 25$$ and $$a_{10} = 100$$.

In an Arithmetic progression, the first term $$a = 10$$, and last term, $$l = 100$$. The number of terms is $$1000$$. Find their sum.

Find the sum of even numbers between $$11$$ and $$51$$.

Find the sum of fterms of AP whose first term is 26 and last term is 14.

Find the sum of odd numbers between $$0$$ and $$90$$.

What is the sum of first $$100$$ multiples of $$12$$?