Let's get this math done. We have 140 and we're going to multiply it by 30. This is the same as taking 140 and adding it to itself 30 times.
Step 1: 0 + 140 = 140
Step 2: 140 + 140 = 280
Step 3: 280 + 140 = 420
Step 4: 420 + 140 = 560
Step 5: 560 + 140 = 700
Step 6: 700 + 140 = 840
Step 7: 840 + 140 = 980
Step 8: 980 + 140 = 1120
Step 9: 1120 + 140 = 1260
Step 10: 1260 + 140 = 1400
Step 11: 1400 + 140 = 1540
Step 12: 1540 + 140 = 1680
Step 13: 1680 + 140 = 1820
Step 14: 1820 + 140 = 1960
Step 15: 1960 + 140 = 2100
Step 16: 2100 + 140 = 2240
Step 17: 2240 + 140 = 2380
Step 18: 2380 + 140 = 2520
Step 19: 2520 + 140 = 2660
Step 20: 2660 + 140 = 2800
Step 21: 2800 + 140 = 2940
Step 22: 2940 + 140 = 3080
Step 23: 3080 + 140 = 3220
Step 24: 3220 + 140 = 3360
Step 25: 3360 + 140 = 3500
Step 26: 3500 + 140 = 3640
Step 27: 3640 + 140 = 3780
Step 28: 3780 + 140 = 3920
Step 29: 3920 + 140 = 4060
Step 30: 4060 + 140 = 4200

So, 140*30 = 4200