Alright, let's solve this math problem step by step. First, we have the number 864. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 400. So, we're going to take the number 864 and add it to itself 400 times.
Step 1: 0 + 864 = 864
Step 2: 864 + 864 = 1728
Step 3: 1728 + 864 = 2592
Step 4: 2592 + 864 = 3456
Step 5: 3456 + 864 = 4320
Step 6: 4320 + 864 = 5184
Step 7: 5184 + 864 = 6048
Step 8: 6048 + 864 = 6912
Step 9: 6912 + 864 = 7776
Step 10: 7776 + 864 = 8640
Step 11: 8640 + 864 = 9504
Step 12: 9504 + 864 = 10368
Step 13: 10368 + 864 = 11232
Step 14: 11232 + 864 = 12096
Step 15: 12096 + 864 = 12960
Step 16: 12960 + 864 = 13824
Step 17: 13824 + 864 = 14688
Step 18: 14688 + 864 = 15552
Step 19: 15552 + 864 = 16416
Step 20: 16416 + 864 = 17280
Step 21: 17280 + 864 = 18144
Step 22: 18144 + 864 = 19008
Step 23: 19008 + 864 = 19872
Step 24: 19872 + 864 = 20736
Step 25: 20736 + 864 = 21600
Step 26: 21600 + 864 = 22464
Step 27: 22464 + 864 = 23328
Step 28: 23328 + 864 = 24192
Step 29: 24192 + 864 = 25056
Step 30: 25056 + 864 = 25920
Step 31: 25920 + 864 = 26784
Step 32: 26784 + 864 = 27648
Step 33: 27648 + 864 = 28512
Step 34: 28512 + 864 = 29376
Step 35: 29376 + 864 = 30240
Step 36: 30240 + 864 = 31104
Step 37: 31104 + 864 = 31968
Step 38: 31968 + 864 = 32832
Step 39: 32832 + 864 = 33696
Step 40: 33696 + 864 = 34560
Step 41: 34560 + 864 = 35424
Step 42: 35424 + 864 = 36288
Step 43: 36288 + 864 = 37152
Step 44: 37152 + 864 = 38016
Step 45: 38016 + 864 = 38880
Step 46: 38880 + 864 = 39744
Step 47: 39744 + 864 = 40608
Step 48: 40608 + 864 = 41472
Step 49: 41472 + 864 = 42336
Step 50: 42336 + 864 = 43200
Step 51: 43200 + 864 = 44064
Step 52: 44064 + 864 = 44928
Step 53: 44928 + 864 = 45792
Step 54: 45792 + 864 = 46656
Step 55: 46656 + 864 = 47520
Step 56: 47520 + 864 = 48384
Step 57: 48384 + 864 = 49248
Step 58: 49248 + 864 = 50112
Step 59: 50112 + 864 = 50976
Step 60: 50976 + 864 = 51840
Step 61: 51840 + 864 = 52704
Step 62: 52704 + 864 = 53568
Step 63: 53568 + 864 = 54432
Step 64: 54432 + 864 = 55296
Step 65: 55296 + 864 = 56160
Step 66: 56160 + 864 = 57024
Step 67: 57024 + 864 = 57888
Step 68: 57888 + 864 = 58752
Step 69: 58752 + 864 = 59616
Step 70: 59616 + 864 = 60480
Step 71: 60480 + 864 = 61344
Step 72: 61344 + 864 = 62208
Step 73: 62208 + 864 = 63072
Step 74: 63072 + 864 = 63936
Step 75: 63936 + 864 = 64800
Step 76: 64800 + 864 = 65664
Step 77: 65664 + 864 = 66528
Step 78: 66528 + 864 = 67392
Step 79: 67392 + 864 = 68256
Step 80: 68256 + 864 = 69120
Step 81: 69120 + 864 = 69984
Step 82: 69984 + 864 = 70848
Step 83: 70848 + 864 = 71712
Step 84: 71712 + 864 = 72576
Step 85: 72576 + 864 = 73440
Step 86: 73440 + 864 = 74304
Step 87: 74304 + 864 = 75168
Step 88: 75168 + 864 = 76032
Step 89: 76032 + 864 = 76896
Step 90: 76896 + 864 = 77760
Step 91: 77760 + 864 = 78624
Step 92: 78624 + 864 = 79488
Step 93: 79488 + 864 = 80352
Step 94: 80352 + 864 = 81216
Step 95: 81216 + 864 = 82080
Step 96: 82080 + 864 = 82944
Step 97: 82944 + 864 = 83808
Step 98: 83808 + 864 = 84672
Step 99: 84672 + 864 = 85536
Step 100: 85536 + 864 = 86400
Step 101: 86400 + 864 = 87264
Step 102: 87264 + 864 = 88128
Step 103: 88128 + 864 = 88992
Step 104: 88992 + 864 = 89856
Step 105: 89856 + 864 = 90720
Step 106: 90720 + 864 = 91584
Step 107: 91584 + 864 = 92448
Step 108: 92448 + 864 = 93312
Step 109: 93312 + 864 = 94176
Step 110: 94176 + 864 = 95040
Step 111: 95040 + 864 = 95904
Step 112: 95904 + 864 = 96768
Step 113: 96768 + 864 = 97632
Step 114: 97632 + 864 = 98496
Step 115: 98496 + 864 = 99360
Step 116: 99360 + 864 = 100224
Step 117: 100224 + 864 = 101088
Step 118: 101088 + 864 = 101952
Step 119: 101952 + 864 = 102816
Step 120: 102816 + 864 = 103680
Step 121: 103680 + 864 = 104544
Step 122: 104544 + 864 = 105408
Step 123: 105408 + 864 = 106272
Step 124: 106272 + 864 = 107136
Step 125: 107136 + 864 = 108000
Step 126: 108000 + 864 = 108864
Step 127: 108864 + 864 = 109728
Step 128: 109728 + 864 = 110592
Step 129: 110592 + 864 = 111456
Step 130: 111456 + 864 = 112320
Step 131: 112320 + 864 = 113184
Step 132: 113184 + 864 = 114048
Step 133: 114048 + 864 = 114912
Step 134: 114912 + 864 = 115776
Step 135: 115776 + 864 = 116640
Step 136: 116640 + 864 = 117504
Step 137: 117504 + 864 = 118368
Step 138: 118368 + 864 = 119232
Step 139: 119232 + 864 = 120096
Step 140: 120096 + 864 = 120960
Step 141: 120960 + 864 = 121824
Step 142: 121824 + 864 = 122688
Step 143: 122688 + 864 = 123552
Step 144: 123552 + 864 = 124416
Step 145: 124416 + 864 = 125280
Step 146: 125280 + 864 = 126144
Step 147: 126144 + 864 = 127008
Step 148: 127008 + 864 = 127872
Step 149: 127872 + 864 = 128736
Step 150: 128736 + 864 = 129600
Step 151: 129600 + 864 = 130464
Step 152: 130464 + 864 = 131328
Step 153: 131328 + 864 = 132192
Step 154: 132192 + 864 = 133056
Step 155: 133056 + 864 = 133920
Step 156: 133920 + 864 = 134784
Step 157: 134784 + 864 = 135648
Step 158: 135648 + 864 = 136512
Step 159: 136512 + 864 = 137376
Step 160: 137376 + 864 = 138240
Step 161: 138240 + 864 = 139104
Step 162: 139104 + 864 = 139968
Step 163: 139968 + 864 = 140832
Step 164: 140832 + 864 = 141696
Step 165: 141696 + 864 = 142560
Step 166: 142560 + 864 = 143424
Step 167: 143424 + 864 = 144288
Step 168: 144288 + 864 = 145152
Step 169: 145152 + 864 = 146016
Step 170: 146016 + 864 = 146880
Step 171: 146880 + 864 = 147744
Step 172: 147744 + 864 = 148608
Step 173: 148608 + 864 = 149472
Step 174: 149472 + 864 = 150336
Step 175: 150336 + 864 = 151200
Step 176: 151200 + 864 = 152064
Step 177: 152064 + 864 = 152928
Step 178: 152928 + 864 = 153792
Step 179: 153792 + 864 = 154656
Step 180: 154656 + 864 = 155520
Step 181: 155520 + 864 = 156384
Step 182: 156384 + 864 = 157248
Step 183: 157248 + 864 = 158112
Step 184: 158112 + 864 = 158976
Step 185: 158976 + 864 = 159840
Step 186: 159840 + 864 = 160704
Step 187: 160704 + 864 = 161568
Step 188: 161568 + 864 = 162432
Step 189: 162432 + 864 = 163296
Step 190: 163296 + 864 = 164160
Step 191: 164160 + 864 = 165024
Step 192: 165024 + 864 = 165888
Step 193: 165888 + 864 = 166752
Step 194: 166752 + 864 = 167616
Step 195: 167616 + 864 = 168480
Step 196: 168480 + 864 = 169344
Step 197: 169344 + 864 = 170208
Step 198: 170208 + 864 = 171072
Step 199: 171072 + 864 = 171936
Step 200: 171936 + 864 = 172800
Step 201: 172800 + 864 = 173664
Step 202: 173664 + 864 = 174528
Step 203: 174528 + 864 = 175392
Step 204: 175392 + 864 = 176256
Step 205: 176256 + 864 = 177120
Step 206: 177120 + 864 = 177984
Step 207: 177984 + 864 = 178848
Step 208: 178848 + 864 = 179712
Step 209: 179712 + 864 = 180576
Step 210: 180576 + 864 = 181440
Step 211: 181440 + 864 = 182304
Step 212: 182304 + 864 = 183168
Step 213: 183168 + 864 = 184032
Step 214: 184032 + 864 = 184896
Step 215: 184896 + 864 = 185760
Step 216: 185760 + 864 = 186624
Step 217: 186624 + 864 = 187488
Step 218: 187488 + 864 = 188352
Step 219: 188352 + 864 = 189216
Step 220: 189216 + 864 = 190080
Step 221: 190080 + 864 = 190944
Step 222: 190944 + 864 = 191808
Step 223: 191808 + 864 = 192672
Step 224: 192672 + 864 = 193536
Step 225: 193536 + 864 = 194400
Step 226: 194400 + 864 = 195264
Step 227: 195264 + 864 = 196128
Step 228: 196128 + 864 = 196992
Step 229: 196992 + 864 = 197856
Step 230: 197856 + 864 = 198720
Step 231: 198720 + 864 = 199584
Step 232: 199584 + 864 = 200448
Step 233: 200448 + 864 = 201312
Step 234: 201312 + 864 = 202176
Step 235: 202176 + 864 = 203040
Step 236: 203040 + 864 = 203904
Step 237: 203904 + 864 = 204768
Step 238: 204768 + 864 = 205632
Step 239: 205632 + 864 = 206496
Step 240: 206496 + 864 = 207360
Step 241: 207360 + 864 = 208224
Step 242: 208224 + 864 = 209088
Step 243: 209088 + 864 = 209952
Step 244: 209952 + 864 = 210816
Step 245: 210816 + 864 = 211680
Step 246: 211680 + 864 = 212544
Step 247: 212544 + 864 = 213408
Step 248: 213408 + 864 = 214272
Step 249: 214272 + 864 = 215136
Step 250: 215136 + 864 = 216000
Step 251: 216000 + 864 = 216864
Step 252: 216864 + 864 = 217728
Step 253: 217728 + 864 = 218592
Step 254: 218592 + 864 = 219456
Step 255: 219456 + 864 = 220320
Step 256: 220320 + 864 = 221184
Step 257: 221184 + 864 = 222048
Step 258: 222048 + 864 = 222912
Step 259: 222912 + 864 = 223776
Step 260: 223776 + 864 = 224640
Step 261: 224640 + 864 = 225504
Step 262: 225504 + 864 = 226368
Step 263: 226368 + 864 = 227232
Step 264: 227232 + 864 = 228096
Step 265: 228096 + 864 = 228960
Step 266: 228960 + 864 = 229824
Step 267: 229824 + 864 = 230688
Step 268: 230688 + 864 = 231552
Step 269: 231552 + 864 = 232416
Step 270: 232416 + 864 = 233280
Step 271: 233280 + 864 = 234144
Step 272: 234144 + 864 = 235008
Step 273: 235008 + 864 = 235872
Step 274: 235872 + 864 = 236736
Step 275: 236736 + 864 = 237600
Step 276: 237600 + 864 = 238464
Step 277: 238464 + 864 = 239328
Step 278: 239328 + 864 = 240192
Step 279: 240192 + 864 = 241056
Step 280: 241056 + 864 = 241920
Step 281: 241920 + 864 = 242784
Step 282: 242784 + 864 = 243648
Step 283: 243648 + 864 = 244512
Step 284: 244512 + 864 = 245376
Step 285: 245376 + 864 = 246240
Step 286: 246240 + 864 = 247104
Step 287: 247104 + 864 = 247968
Step 288: 247968 + 864 = 248832
Step 289: 248832 + 864 = 249696
Step 290: 249696 + 864 = 250560
Step 291: 250560 + 864 = 251424
Step 292: 251424 + 864 = 252288
Step 293: 252288 + 864 = 253152
Step 294: 253152 + 864 = 254016
Step 295: 254016 + 864 = 254880
Step 296: 254880 + 864 = 255744
Step 297: 255744 + 864 = 256608
Step 298: 256608 + 864 = 257472
Step 299: 257472 + 864 = 258336
Step 300: 258336 + 864 = 259200
Step 301: 259200 + 864 = 260064
Step 302: 260064 + 864 = 260928
Step 303: 260928 + 864 = 261792
Step 304: 261792 + 864 = 262656
Step 305: 262656 + 864 = 263520
Step 306: 263520 + 864 = 264384
Step 307: 264384 + 864 = 265248
Step 308: 265248 + 864 = 266112
Step 309: 266112 + 864 = 266976
Step 310: 266976 + 864 = 267840
Step 311: 267840 + 864 = 268704
Step 312: 268704 + 864 = 269568
Step 313: 269568 + 864 = 270432
Step 314: 270432 + 864 = 271296
Step 315: 271296 + 864 = 272160
Step 316: 272160 + 864 = 273024
Step 317: 273024 + 864 = 273888
Step 318: 273888 + 864 = 274752
Step 319: 274752 + 864 = 275616
Step 320: 275616 + 864 = 276480
Step 321: 276480 + 864 = 277344
Step 322: 277344 + 864 = 278208
Step 323: 278208 + 864 = 279072
Step 324: 279072 + 864 = 279936
Step 325: 279936 + 864 = 280800
Step 326: 280800 + 864 = 281664
Step 327: 281664 + 864 = 282528
Step 328: 282528 + 864 = 283392
Step 329: 283392 + 864 = 284256
Step 330: 284256 + 864 = 285120
Step 331: 285120 + 864 = 285984
Step 332: 285984 + 864 = 286848
Step 333: 286848 + 864 = 287712
Step 334: 287712 + 864 = 288576
Step 335: 288576 + 864 = 289440
Step 336: 289440 + 864 = 290304
Step 337: 290304 + 864 = 291168
Step 338: 291168 + 864 = 292032
Step 339: 292032 + 864 = 292896
Step 340: 292896 + 864 = 293760
Step 341: 293760 + 864 = 294624
Step 342: 294624 + 864 = 295488
Step 343: 295488 + 864 = 296352
Step 344: 296352 + 864 = 297216
Step 345: 297216 + 864 = 298080
Step 346: 298080 + 864 = 298944
Step 347: 298944 + 864 = 299808
Step 348: 299808 + 864 = 300672
Step 349: 300672 + 864 = 301536
Step 350: 301536 + 864 = 302400
Step 351: 302400 + 864 = 303264
Step 352: 303264 + 864 = 304128
Step 353: 304128 + 864 = 304992
Step 354: 304992 + 864 = 305856
Step 355: 305856 + 864 = 306720
Step 356: 306720 + 864 = 307584
Step 357: 307584 + 864 = 308448
Step 358: 308448 + 864 = 309312
Step 359: 309312 + 864 = 310176
Step 360: 310176 + 864 = 311040
Step 361: 311040 + 864 = 311904
Step 362: 311904 + 864 = 312768
Step 363: 312768 + 864 = 313632
Step 364: 313632 + 864 = 314496
Step 365: 314496 + 864 = 315360
Step 366: 315360 + 864 = 316224
Step 367: 316224 + 864 = 317088
Step 368: 317088 + 864 = 317952
Step 369: 317952 + 864 = 318816
Step 370: 318816 + 864 = 319680
Step 371: 319680 + 864 = 320544
Step 372: 320544 + 864 = 321408
Step 373: 321408 + 864 = 322272
Step 374: 322272 + 864 = 323136
Step 375: 323136 + 864 = 324000
Step 376: 324000 + 864 = 324864
Step 377: 324864 + 864 = 325728
Step 378: 325728 + 864 = 326592
Step 379: 326592 + 864 = 327456
Step 380: 327456 + 864 = 328320
Step 381: 328320 + 864 = 329184
Step 382: 329184 + 864 = 330048
Step 383: 330048 + 864 = 330912
Step 384: 330912 + 864 = 331776
Step 385: 331776 + 864 = 332640
Step 386: 332640 + 864 = 333504
Step 387: 333504 + 864 = 334368
Step 388: 334368 + 864 = 335232
Step 389: 335232 + 864 = 336096
Step 390: 336096 + 864 = 336960
Step 391: 336960 + 864 = 337824
Step 392: 337824 + 864 = 338688
Step 393: 338688 + 864 = 339552
Step 394: 339552 + 864 = 340416
Step 395: 340416 + 864 = 341280
Step 396: 341280 + 864 = 342144
Step 397: 342144 + 864 = 343008
Step 398: 343008 + 864 = 343872
Step 399: 343872 + 864 = 344736
Step 400: 344736 + 864 = 345600

So, 864*400 = 345600