Question

PLEASE HELP!

How many whole numbers between 99 and 999 contain exactly one 0?

Answer 1

162
Here they are
{101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 120, 130, 140, \
150, 160, 170, 180, 190, 201, 202, 203, 204, 205, 206, 207, 208, 209, \
210, 220, 230, 240, 250, 260, 270, 280, 290, 301, 302, 303, 304, 305, \
306, 307, 308, 309, 310, 320, 330, 340, 350, 360, 370, 380, 390, 401, \
402, 403, 404, 405, 406, 407, 408, 409, 410, 420, 430, 440, 450, 460, \
470, 480, 490, 501, 502, 503, 504, 505, 506, 507, 508, 509, 510, 520, \
530, 540, 550, 560, 570, 580, 590, 601, 602, 603, 604, 605, 606, 607, \
608, 609, 610, 620, 630, 640, 650, 660, 670, 680, 690, 701, 702, 703, \
704, 705, 706, 707, 708, 709, 710, 720, 730, 740, 750, 760, 770, 780, \
790, 801, 802, 803, 804, 805, 806, 807, 808, 809, 810, 820, 830, 840, \
850, 860, 870, 880, 890, 901, 902, 903, 904, 905, 906, 907, 908, 909, \
910, 920, 930, 940, 950, 960, 970, 980, 990}