 mersenneforum.org M51 arithmetic
 Register FAQ Search Today's Posts Mark Forums Read  2019-01-22, 17:02 #89 henryzz Just call me Henry   "David" Sep 2007 Cambridge (GMT/BST) 23×739 Posts 357 = 8-2+5*8*9+L3D[-9] 359 = -8/2+5*8*9 + L3D 360 = 8-2+5*8*9+L3D[-6] 361 = 8+2+5*8*9+L3D[-9] 362 to 370 = 8-2+5*8*9 + L3D[-4 to 4] 371 to 374 = 8+2+5*8*9 + L3D[1 to 4] 375 to 380 = 8*2+5*8*9 + L3D[-1 to 4] 381 = (8+2)*5*8 + L4D[-19] 382 to 390 = 8+(2+5*8)*9 + L3D[-4 to 4] 391 to 413 = (8+2)*5*8 + L4D[-9 to 13] 414 to 418 = (8-2+5*8)*9 + L3D[0 to 4] 419 = (8+2)*5*8 + L4D 420 = (8-2+5*8)*9 + L3D 421 = (8+2)*5*8 + L4D 422 to 424 = (8-2+5*8)*9 + L3D[8 to 10] And that's enough from me for a bit.   2019-01-23, 16:35   #90
PhilF

"6800 descendent"
Feb 2005

23·5·17 Posts Quote:
 Originally Posted by henryzz How didn't I spot that trivial 5*8*9=360?
My math skills are so trivial that I find this non-trivial:

Someone born in 33 was 45 in 78.

You have to be old enough to get it. At least I qualify there!    2019-01-29, 15:36 #91 henryzz Just call me Henry   "David" Sep 2007 Cambridge (GMT/BST) 171816 Posts 425 is still needed. 426 = ((8+2)+5*8)*9 - 9*3+3 427 = 8*(2+5)*8 + L4D[-21] 428 = (-8+(2+5)*8)*9 +L3D[-4] 429 to 431 = 8*(2+5)*8 + L4D[-19 to -17] 432 = 8/2*(5+8)*9 - (9+3)*3 433 = 8*(2+5)*8 + L4D[-15] 434 to 461 = 8*(2+5)*8 + L4D[-13 to 13] 462 = 8/2*(5+8)*9 + L3D[-6] 463 = (8+2)*(5*8+(9+9)/3)+3 464 to 472 = 8/2*(5+8)*9 + L3D[-4 to 4] Last fiddled with by henryzz on 2019-01-29 at 15:36   2019-01-29, 16:16   #92
retina
Undefined

"The unspeakable one"
Jun 2006
My evil lair

627910 Posts Quote:
 Originally Posted by henryzz 425 is still needed.
It's a multiple of 5 so: 8+2+5*(8+9*9-3-3)   2019-01-30, 08:22 #93 retina Undefined   "The unspeakable one" Jun 2006 My evil lair 3·7·13·23 Posts 473 isn't much different from 425. 473 8+2+5*(8+9*9+3)+3   2019-01-30, 09:41 #94 retina Undefined   "The unspeakable one" Jun 2006 My evil lair 3×7×13×23 Posts We can get 504 as a base from the first 5 digits 504 = (8*2+5*8)*9 So that gives us 474 with 474 = (8*2+5*8)*9-(9*3+3)   2019-01-30, 11:07 #95 henryzz Just call me Henry   "David" Sep 2007 Cambridge (GMT/BST) 591210 Posts a bunch of L3D solutions: 15 = 9+3+3 18 = 9+3*3 24 = 9*3-3 30 = 9*3+3 36 = (9+3)*3 Various numbers can be solved based on: 490 = (8+2)*(5*8+9) 475 = (8+2)*(5*8+9) + L3D[-15] 480 to 482 = (8+2)*(5*8+9) + L3D[-10 to -8] 484 = (8+2)*(5*8+9) + L3D[-6] 486 to 494 = (8+2)*(5*8+9) + L3D[-4 to 4] 496 = (8+2)*(5*8+9) + L3D 498 to 500 = (8+2)*(5*8+9) + L3D[8 to 10] 505 = (8+2)*(5*8+9) + L3D 508 = (8+2)*(5*8+9) + L3D 514 = (8+2)*(5*8+9) + L3D 520 = (8+2)*(5*8+9) + L3D 526 = (8+2)*(5*8+9) + L3D retina's 504 produces: 495 = (8*2+5*8)*9 + L3D[-9] 501 to 504 = (8*2+5*8)*9 + L3D[-3 to 0] 506 to 507 = (8*2+5*8)*9 + L3D[2 to 3] 510 = (8*2+5*8)*9 + L3D 512 to 513 = (8*2+5*8)*9 + L3D[8 to 9] 519 = (8*2+5*8)*9 + L3D 522 = (8*2+5*8)*9 + L3D 528 = (8*2+5*8)*9 + L3D 534 = (8*2+5*8)*9 + L3D 540 = (8*2+5*8)*9 + L3D   2019-01-31, 14:57 #96 henryzz Just call me Henry   "David" Sep 2007 Cambridge (GMT/BST) 10111000110002 Posts 496 = 8*2*(5*8-9) produces: 478 = 8*2*(5*8-9) + L3D[-18] 497 = 8*2*(5*8-9) + L3D 511 = 8*2*(5*8-9) + L3D 532 = 8*2*(5*8-9) + L3D 510 = (8-2)*5*(8+9) produces: 509 = (8-2)*5*(8+9) + L3D[-1] 516 = (8-2)*5*(8+9) + L3D 518 = (8-2)*5*(8+9) + L3D 525 = (8-2)*5*(8+9) + L3D 546 = (8-2)*5*(8+9) + L3D 512 = 8+(2+5)*8*9 produces: 476 = 8+(2+5)*8*9 + L3D[-36] 515 = 8+(2+5)*8*9 + L3D 521 = 8+(2+5)*8*9 + L3D 527 = 8+(2+5)*8*9 + L3D 530 = 8+(2+5)*8*9 + L3D 536 = 8+(2+5)*8*9 + L3D 542 = 8+(2+5)*8*9 + L3D 548 = 8+(2+5)*8*9 + L3D This leaves only 4 left to reach 500: 477, 479, 483, 485   2019-01-31, 15:13 #97 retina Undefined   "The unspeakable one" Jun 2006 My evil lair 3·7·13·23 Posts Another 5 digit base 468 = 8/(2/(5+8)/9) Another way to write it is 8/(2/(5+8))*9 Leads to 477 = 8/(2/(5+8)/9)+9-3+3 Last fiddled with by retina on 2019-01-31 at 15:16   2019-01-31, 16:07 #98 henryzz Just call me Henry   "David" Sep 2007 Cambridge (GMT/BST) 23×739 Posts That 468 also leads to: 483 = 8/(2/(5+8)/9) + L3D   2019-01-31, 16:16 #99 retina Undefined   "The unspeakable one" Jun 2006 My evil lair 3×7×13×23 Posts 479 = (8+2)*5+8*9*(9-3)-3 I'll leave it to someone else to discover 485   Thread Tools Show Printable Version Email this Page Similar Threads Thread Thread Starter Forum Replies Last Post ewmayer Science & Technology 34 2015-10-03 01:31 science_man_88 science_man_88 11 2014-07-30 22:53 science_man_88 Miscellaneous Math 42 2011-07-26 02:02 mfgoode Puzzles 82 2007-05-02 08:13 R.D. Silverman Factoring 3 2006-06-05 23:49

All times are UTC. The time now is 13:12.

Sun Oct 17 13:12:07 UTC 2021 up 86 days, 7:41, 0 users, load averages: 1.94, 1.73, 1.98