2. Multiply each bit by its corresponding power of 2 and add all the terms up.
1111 0000 1101 1110 1011 1100 1001 1010 0111 1000 0101 0110 0011 0100 0001 1000(2) =
(1 × 263 + 1 × 262 + 1 × 261 + 1 × 260 + 0 × 259 + 0 × 258 + 0 × 257 + 0 × 256 + 1 × 255 + 1 × 254 + 0 × 253 + 1 × 252 + 1 × 251 + 1 × 250 + 1 × 249 + 0 × 248 + 1 × 247 + 0 × 246 + 1 × 245 + 1 × 244 + 1 × 243 + 1 × 242 + 0 × 241 + 0 × 240 + 1 × 239 + 0 × 238 + 0 × 237 + 1 × 236 + 1 × 235 + 0 × 234 + 1 × 233 + 0 × 232 + 0 × 231 + 1 × 230 + 1 × 229 + 1 × 228 + 1 × 227 + 0 × 226 + 0 × 225 + 0 × 224 + 0 × 223 + 1 × 222 + 0 × 221 + 1 × 220 + 0 × 219 + 1 × 218 + 1 × 217 + 0 × 216 + 0 × 215 + 0 × 214 + 1 × 213 + 1 × 212 + 0 × 211 + 1 × 210 + 0 × 29 + 0 × 28 + 0 × 27 + 0 × 26 + 0 × 25 + 1 × 24 + 1 × 23 + 0 × 22 + 0 × 21 + 0 × 20)(10) =
(9 223 372 036 854 775 808 + 4 611 686 018 427 387 904 + 2 305 843 009 213 693 952 + 1 152 921 504 606 846 976 + 0 + 0 + 0 + 0 + 36 028 797 018 963 968 + 18 014 398 509 481 984 + 0 + 4 503 599 627 370 496 + 2 251 799 813 685 248 + 1 125 899 906 842 624 + 562 949 953 421 312 + 0 + 140 737 488 355 328 + 0 + 35 184 372 088 832 + 17 592 186 044 416 + 8 796 093 022 208 + 4 398 046 511 104 + 0 + 0 + 549 755 813 888 + 0 + 0 + 68 719 476 736 + 34 359 738 368 + 0 + 8 589 934 592 + 0 + 0 + 1 073 741 824 + 536 870 912 + 268 435 456 + 134 217 728 + 0 + 0 + 0 + 0 + 4 194 304 + 0 + 1 048 576 + 0 + 262 144 + 131 072 + 0 + 0 + 0 + 8 192 + 4 096 + 0 + 1 024 + 0 + 0 + 0 + 0 + 0 + 16 + 8 + 0 + 0 + 0)(10) =
(9 223 372 036 854 775 808 + 4 611 686 018 427 387 904 + 2 305 843 009 213 693 952 + 1 152 921 504 606 846 976 + 36 028 797 018 963 968 + 18 014 398 509 481 984 + 4 503 599 627 370 496 + 2 251 799 813 685 248 + 1 125 899 906 842 624 + 562 949 953 421 312 + 140 737 488 355 328 + 35 184 372 088 832 + 17 592 186 044 416 + 8 796 093 022 208 + 4 398 046 511 104 + 549 755 813 888 + 68 719 476 736 + 34 359 738 368 + 8 589 934 592 + 1 073 741 824 + 536 870 912 + 268 435 456 + 134 217 728 + 4 194 304 + 1 048 576 + 262 144 + 131 072 + 8 192 + 4 096 + 1 024 + 16 + 8)(10) =
17 356 517 385 562 371 096(10)
The number 1111 0000 1101 1110 1011 1100 1001 1010 0111 1000 0101 0110 0011 0100 0001 1000(2) converted from an unsigned binary (in base 2) and written as a positive integer (with no sign) in decimal system (in base ten):
1111 0000 1101 1110 1011 1100 1001 1010 0111 1000 0101 0110 0011 0100 0001 1000(2) = 17 356 517 385 562 371 096(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.