just add them 1+3+5+7+9+11+13+15+17+19 = 100
or a trick you could use is realize that
19 + 1 = 20
17 + 3 = 20
15 + 5 = 20
13 + 7 = 20
11 + 9 = 20
20 x 5 (total pairings or half the numbers your adding) = 100
The average is 10. You will find that the average when adding together the first n odd numbers is always equal to n.
2500
The first 20 odd numbers are: 13579111315171921232527293133353739.
The first 85 odd numbers are: 1 3579111315171921232527293133353739414345474951535557596163656769717375777981838587899193959799101103105107109111113115117119121123125127129131133135137139141143145147149151153155157159161163165167169.
The sum of the first 8,000 odd numbers 64,000,000.
algorithim and flow chart of odd number 1 and 50
2500
The average is 10. You will find that the average when adding together the first n odd numbers is always equal to n.
The first 20 odd numbers are: 13579111315171921232527293133353739.
The first 100 odd whole numbers are: 13579111315171921232527293133353739414345474951535557596163656769717375777981838587899193959799101103105107109111113115117119121123125127129131133135137139141143145147149151153155157159161163165167169171173175177179181183185187189191193195197199.
The first 85 odd numbers are: 1 3579111315171921232527293133353739414345474951535557596163656769717375777981838587899193959799101103105107109111113115117119121123125127129131133135137139141143145147149151153155157159161163165167169.
The sum of the first 15 odd numbers is 225.
The sum of the first 300 odd numbers is 90,000
The sum of the first 40 odd numbers is 1,600.
The sum of the first 8,000 odd numbers 64,000,000.
The sum of the first 600 odd numbers is 360,000.
The sum of the first nine odd numbers is 81.