Alright, let's solve this math problem step by step. First, we have the number 690. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 309. So, we're going to take the number 690 and add it to itself 309 times.
Step 1: 0 + 690 = 690
Step 2: 690 + 690 = 1380
Step 3: 1380 + 690 = 2070
Step 4: 2070 + 690 = 2760
Step 5: 2760 + 690 = 3450
Step 6: 3450 + 690 = 4140
Step 7: 4140 + 690 = 4830
Step 8: 4830 + 690 = 5520
Step 9: 5520 + 690 = 6210
Step 10: 6210 + 690 = 6900
Step 11: 6900 + 690 = 7590
Step 12: 7590 + 690 = 8280
Step 13: 8280 + 690 = 8970
Step 14: 8970 + 690 = 9660
Step 15: 9660 + 690 = 10350
Step 16: 10350 + 690 = 11040
Step 17: 11040 + 690 = 11730
Step 18: 11730 + 690 = 12420
Step 19: 12420 + 690 = 13110
Step 20: 13110 + 690 = 13800
Step 21: 13800 + 690 = 14490
Step 22: 14490 + 690 = 15180
Step 23: 15180 + 690 = 15870
Step 24: 15870 + 690 = 16560
Step 25: 16560 + 690 = 17250
Step 26: 17250 + 690 = 17940
Step 27: 17940 + 690 = 18630
Step 28: 18630 + 690 = 19320
Step 29: 19320 + 690 = 20010
Step 30: 20010 + 690 = 20700
Step 31: 20700 + 690 = 21390
Step 32: 21390 + 690 = 22080
Step 33: 22080 + 690 = 22770
Step 34: 22770 + 690 = 23460
Step 35: 23460 + 690 = 24150
Step 36: 24150 + 690 = 24840
Step 37: 24840 + 690 = 25530
Step 38: 25530 + 690 = 26220
Step 39: 26220 + 690 = 26910
Step 40: 26910 + 690 = 27600
Step 41: 27600 + 690 = 28290
Step 42: 28290 + 690 = 28980
Step 43: 28980 + 690 = 29670
Step 44: 29670 + 690 = 30360
Step 45: 30360 + 690 = 31050
Step 46: 31050 + 690 = 31740
Step 47: 31740 + 690 = 32430
Step 48: 32430 + 690 = 33120
Step 49: 33120 + 690 = 33810
Step 50: 33810 + 690 = 34500
Step 51: 34500 + 690 = 35190
Step 52: 35190 + 690 = 35880
Step 53: 35880 + 690 = 36570
Step 54: 36570 + 690 = 37260
Step 55: 37260 + 690 = 37950
Step 56: 37950 + 690 = 38640
Step 57: 38640 + 690 = 39330
Step 58: 39330 + 690 = 40020
Step 59: 40020 + 690 = 40710
Step 60: 40710 + 690 = 41400
Step 61: 41400 + 690 = 42090
Step 62: 42090 + 690 = 42780
Step 63: 42780 + 690 = 43470
Step 64: 43470 + 690 = 44160
Step 65: 44160 + 690 = 44850
Step 66: 44850 + 690 = 45540
Step 67: 45540 + 690 = 46230
Step 68: 46230 + 690 = 46920
Step 69: 46920 + 690 = 47610
Step 70: 47610 + 690 = 48300
Step 71: 48300 + 690 = 48990
Step 72: 48990 + 690 = 49680
Step 73: 49680 + 690 = 50370
Step 74: 50370 + 690 = 51060
Step 75: 51060 + 690 = 51750
Step 76: 51750 + 690 = 52440
Step 77: 52440 + 690 = 53130
Step 78: 53130 + 690 = 53820
Step 79: 53820 + 690 = 54510
Step 80: 54510 + 690 = 55200
Step 81: 55200 + 690 = 55890
Step 82: 55890 + 690 = 56580
Step 83: 56580 + 690 = 57270
Step 84: 57270 + 690 = 57960
Step 85: 57960 + 690 = 58650
Step 86: 58650 + 690 = 59340
Step 87: 59340 + 690 = 60030
Step 88: 60030 + 690 = 60720
Step 89: 60720 + 690 = 61410
Step 90: 61410 + 690 = 62100
Step 91: 62100 + 690 = 62790
Step 92: 62790 + 690 = 63480
Step 93: 63480 + 690 = 64170
Step 94: 64170 + 690 = 64860
Step 95: 64860 + 690 = 65550
Step 96: 65550 + 690 = 66240
Step 97: 66240 + 690 = 66930
Step 98: 66930 + 690 = 67620
Step 99: 67620 + 690 = 68310
Step 100: 68310 + 690 = 69000
Step 101: 69000 + 690 = 69690
Step 102: 69690 + 690 = 70380
Step 103: 70380 + 690 = 71070
Step 104: 71070 + 690 = 71760
Step 105: 71760 + 690 = 72450
Step 106: 72450 + 690 = 73140
Step 107: 73140 + 690 = 73830
Step 108: 73830 + 690 = 74520
Step 109: 74520 + 690 = 75210
Step 110: 75210 + 690 = 75900
Step 111: 75900 + 690 = 76590
Step 112: 76590 + 690 = 77280
Step 113: 77280 + 690 = 77970
Step 114: 77970 + 690 = 78660
Step 115: 78660 + 690 = 79350
Step 116: 79350 + 690 = 80040
Step 117: 80040 + 690 = 80730
Step 118: 80730 + 690 = 81420
Step 119: 81420 + 690 = 82110
Step 120: 82110 + 690 = 82800
Step 121: 82800 + 690 = 83490
Step 122: 83490 + 690 = 84180
Step 123: 84180 + 690 = 84870
Step 124: 84870 + 690 = 85560
Step 125: 85560 + 690 = 86250
Step 126: 86250 + 690 = 86940
Step 127: 86940 + 690 = 87630
Step 128: 87630 + 690 = 88320
Step 129: 88320 + 690 = 89010
Step 130: 89010 + 690 = 89700
Step 131: 89700 + 690 = 90390
Step 132: 90390 + 690 = 91080
Step 133: 91080 + 690 = 91770
Step 134: 91770 + 690 = 92460
Step 135: 92460 + 690 = 93150
Step 136: 93150 + 690 = 93840
Step 137: 93840 + 690 = 94530
Step 138: 94530 + 690 = 95220
Step 139: 95220 + 690 = 95910
Step 140: 95910 + 690 = 96600
Step 141: 96600 + 690 = 97290
Step 142: 97290 + 690 = 97980
Step 143: 97980 + 690 = 98670
Step 144: 98670 + 690 = 99360
Step 145: 99360 + 690 = 100050
Step 146: 100050 + 690 = 100740
Step 147: 100740 + 690 = 101430
Step 148: 101430 + 690 = 102120
Step 149: 102120 + 690 = 102810
Step 150: 102810 + 690 = 103500
Step 151: 103500 + 690 = 104190
Step 152: 104190 + 690 = 104880
Step 153: 104880 + 690 = 105570
Step 154: 105570 + 690 = 106260
Step 155: 106260 + 690 = 106950
Step 156: 106950 + 690 = 107640
Step 157: 107640 + 690 = 108330
Step 158: 108330 + 690 = 109020
Step 159: 109020 + 690 = 109710
Step 160: 109710 + 690 = 110400
Step 161: 110400 + 690 = 111090
Step 162: 111090 + 690 = 111780
Step 163: 111780 + 690 = 112470
Step 164: 112470 + 690 = 113160
Step 165: 113160 + 690 = 113850
Step 166: 113850 + 690 = 114540
Step 167: 114540 + 690 = 115230
Step 168: 115230 + 690 = 115920
Step 169: 115920 + 690 = 116610
Step 170: 116610 + 690 = 117300
Step 171: 117300 + 690 = 117990
Step 172: 117990 + 690 = 118680
Step 173: 118680 + 690 = 119370
Step 174: 119370 + 690 = 120060
Step 175: 120060 + 690 = 120750
Step 176: 120750 + 690 = 121440
Step 177: 121440 + 690 = 122130
Step 178: 122130 + 690 = 122820
Step 179: 122820 + 690 = 123510
Step 180: 123510 + 690 = 124200
Step 181: 124200 + 690 = 124890
Step 182: 124890 + 690 = 125580
Step 183: 125580 + 690 = 126270
Step 184: 126270 + 690 = 126960
Step 185: 126960 + 690 = 127650
Step 186: 127650 + 690 = 128340
Step 187: 128340 + 690 = 129030
Step 188: 129030 + 690 = 129720
Step 189: 129720 + 690 = 130410
Step 190: 130410 + 690 = 131100
Step 191: 131100 + 690 = 131790
Step 192: 131790 + 690 = 132480
Step 193: 132480 + 690 = 133170
Step 194: 133170 + 690 = 133860
Step 195: 133860 + 690 = 134550
Step 196: 134550 + 690 = 135240
Step 197: 135240 + 690 = 135930
Step 198: 135930 + 690 = 136620
Step 199: 136620 + 690 = 137310
Step 200: 137310 + 690 = 138000
Step 201: 138000 + 690 = 138690
Step 202: 138690 + 690 = 139380
Step 203: 139380 + 690 = 140070
Step 204: 140070 + 690 = 140760
Step 205: 140760 + 690 = 141450
Step 206: 141450 + 690 = 142140
Step 207: 142140 + 690 = 142830
Step 208: 142830 + 690 = 143520
Step 209: 143520 + 690 = 144210
Step 210: 144210 + 690 = 144900
Step 211: 144900 + 690 = 145590
Step 212: 145590 + 690 = 146280
Step 213: 146280 + 690 = 146970
Step 214: 146970 + 690 = 147660
Step 215: 147660 + 690 = 148350
Step 216: 148350 + 690 = 149040
Step 217: 149040 + 690 = 149730
Step 218: 149730 + 690 = 150420
Step 219: 150420 + 690 = 151110
Step 220: 151110 + 690 = 151800
Step 221: 151800 + 690 = 152490
Step 222: 152490 + 690 = 153180
Step 223: 153180 + 690 = 153870
Step 224: 153870 + 690 = 154560
Step 225: 154560 + 690 = 155250
Step 226: 155250 + 690 = 155940
Step 227: 155940 + 690 = 156630
Step 228: 156630 + 690 = 157320
Step 229: 157320 + 690 = 158010
Step 230: 158010 + 690 = 158700
Step 231: 158700 + 690 = 159390
Step 232: 159390 + 690 = 160080
Step 233: 160080 + 690 = 160770
Step 234: 160770 + 690 = 161460
Step 235: 161460 + 690 = 162150
Step 236: 162150 + 690 = 162840
Step 237: 162840 + 690 = 163530
Step 238: 163530 + 690 = 164220
Step 239: 164220 + 690 = 164910
Step 240: 164910 + 690 = 165600
Step 241: 165600 + 690 = 166290
Step 242: 166290 + 690 = 166980
Step 243: 166980 + 690 = 167670
Step 244: 167670 + 690 = 168360
Step 245: 168360 + 690 = 169050
Step 246: 169050 + 690 = 169740
Step 247: 169740 + 690 = 170430
Step 248: 170430 + 690 = 171120
Step 249: 171120 + 690 = 171810
Step 250: 171810 + 690 = 172500
Step 251: 172500 + 690 = 173190
Step 252: 173190 + 690 = 173880
Step 253: 173880 + 690 = 174570
Step 254: 174570 + 690 = 175260
Step 255: 175260 + 690 = 175950
Step 256: 175950 + 690 = 176640
Step 257: 176640 + 690 = 177330
Step 258: 177330 + 690 = 178020
Step 259: 178020 + 690 = 178710
Step 260: 178710 + 690 = 179400
Step 261: 179400 + 690 = 180090
Step 262: 180090 + 690 = 180780
Step 263: 180780 + 690 = 181470
Step 264: 181470 + 690 = 182160
Step 265: 182160 + 690 = 182850
Step 266: 182850 + 690 = 183540
Step 267: 183540 + 690 = 184230
Step 268: 184230 + 690 = 184920
Step 269: 184920 + 690 = 185610
Step 270: 185610 + 690 = 186300
Step 271: 186300 + 690 = 186990
Step 272: 186990 + 690 = 187680
Step 273: 187680 + 690 = 188370
Step 274: 188370 + 690 = 189060
Step 275: 189060 + 690 = 189750
Step 276: 189750 + 690 = 190440
Step 277: 190440 + 690 = 191130
Step 278: 191130 + 690 = 191820
Step 279: 191820 + 690 = 192510
Step 280: 192510 + 690 = 193200
Step 281: 193200 + 690 = 193890
Step 282: 193890 + 690 = 194580
Step 283: 194580 + 690 = 195270
Step 284: 195270 + 690 = 195960
Step 285: 195960 + 690 = 196650
Step 286: 196650 + 690 = 197340
Step 287: 197340 + 690 = 198030
Step 288: 198030 + 690 = 198720
Step 289: 198720 + 690 = 199410
Step 290: 199410 + 690 = 200100
Step 291: 200100 + 690 = 200790
Step 292: 200790 + 690 = 201480
Step 293: 201480 + 690 = 202170
Step 294: 202170 + 690 = 202860
Step 295: 202860 + 690 = 203550
Step 296: 203550 + 690 = 204240
Step 297: 204240 + 690 = 204930
Step 298: 204930 + 690 = 205620
Step 299: 205620 + 690 = 206310
Step 300: 206310 + 690 = 207000
Step 301: 207000 + 690 = 207690
Step 302: 207690 + 690 = 208380
Step 303: 208380 + 690 = 209070
Step 304: 209070 + 690 = 209760
Step 305: 209760 + 690 = 210450
Step 306: 210450 + 690 = 211140
Step 307: 211140 + 690 = 211830
Step 308: 211830 + 690 = 212520
Step 309: 212520 + 690 = 213210

So, 690*309 = 213210