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 Re: Mental arithmetic Member 1157700818-Aug-20 2:06 Member 11577008 18-Aug-20 2:06
 Re: Mental arithmetic asimonassi18-Aug-20 2:27 asimonassi 18-Aug-20 2:27
 Re: Mental arithmetic arndibble18-Aug-20 2:34 arndibble 18-Aug-20 2:34
 Re: Mental arithmetic John Godin18-Aug-20 2:57 John Godin 18-Aug-20 2:57
 Re: Mental arithmetic avanishrayankula18-Aug-20 5:01 avanishrayankula 18-Aug-20 5:01
 Re: Mental arithmetic Member 1146760818-Aug-20 6:04 Member 11467608 18-Aug-20 6:04
 This is how I mentally solved it. Well, I used my fingers, also. 10^2 + (10 + 1)^2 + ... + (10 + 4)^2 taking into account (a + b)^2 = a^2 + 2ab + b^2, we have 10^2 appears 5 times: 500 the 2ab term gives: 2 * (10*1 + 10*2 + 10*3 + 10*4) = 20 * (1 + 2 + 3 + 4) = 200; 700, up to now then, the sum of the squares: 1^2 + 2^2 + 3^2 + 4^2 = 1 + 4 + 9 + 16 = 30. numerator sums 730. denominator: 350 + 15, times two gives 700 + 30; answer: 2
 Re: Mental arithmetic jsrjsr18-Aug-20 16:26 jsrjsr 18-Aug-20 16:26
 Re: Mental arithmetic Member 1477127419-Aug-20 5:36 Member 14771274 19-Aug-20 5:36
 Re: Mental arithmetic Stan Rydz19-Aug-20 8:04 Stan Rydz 19-Aug-20 8:04
 Re: Mental arithmetic MrChug19-Aug-20 16:47 MrChug 19-Aug-20 16:47
 Re: Mental arithmetic Kurosh F.30-Aug-20 5:30 Kurosh F. 30-Aug-20 5:30
 Re: Mental arithmetic Member 85731432-Sep-20 20:35 Member 8573143 2-Sep-20 20:35
 Thought of the Day OriginalGriff17-Aug-20 4:31 OriginalGriff 17-Aug-20 4:31
 Re: Thought of the Day W∴ Balboos, GHB17-Aug-20 5:10 W∴ Balboos, GHB 17-Aug-20 5:10
 Re: Thought of the Day Daniel Pfeffer17-Aug-20 5:53 Daniel Pfeffer 17-Aug-20 5:53
 Re: Thought of the Day jsc4217-Aug-20 6:58 jsc42 17-Aug-20 6:58
 Re: Thought of the Day Mike Hankey17-Aug-20 6:47 Mike Hankey 17-Aug-20 6:47
 Re: Thought of the Day Rick York17-Aug-20 7:14 Rick York 17-Aug-20 7:14
 Re: Thought of the Day jeron117-Aug-20 7:26 jeron1 17-Aug-20 7:26
 Re: Thought of the Day DRHuff17-Aug-20 9:20 DRHuff 17-Aug-20 9:20
 Bluetooth blues on Windows 10 - SOLVED? Joan M17-Aug-20 4:01 Joan M 17-Aug-20 4:01
 Just came back from the eye doctor... Sander Rossel17-Aug-20 1:34 Sander Rossel 17-Aug-20 1:34
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