Let's roll up our sleeves and solve this. We have 120 and we're going to multiply it by 35, essentially adding 120 to itself 35 times.
Step 1: 0 + 120 = 120
Step 2: 120 + 120 = 240
Step 3: 240 + 120 = 360
Step 4: 360 + 120 = 480
Step 5: 480 + 120 = 600
Step 6: 600 + 120 = 720
Step 7: 720 + 120 = 840
Step 8: 840 + 120 = 960
Step 9: 960 + 120 = 1080
Step 10: 1080 + 120 = 1200
Step 11: 1200 + 120 = 1320
Step 12: 1320 + 120 = 1440
Step 13: 1440 + 120 = 1560
Step 14: 1560 + 120 = 1680
Step 15: 1680 + 120 = 1800
Step 16: 1800 + 120 = 1920
Step 17: 1920 + 120 = 2040
Step 18: 2040 + 120 = 2160
Step 19: 2160 + 120 = 2280
Step 20: 2280 + 120 = 2400
Step 21: 2400 + 120 = 2520
Step 22: 2520 + 120 = 2640
Step 23: 2640 + 120 = 2760
Step 24: 2760 + 120 = 2880
Step 25: 2880 + 120 = 3000
Step 26: 3000 + 120 = 3120
Step 27: 3120 + 120 = 3240
Step 28: 3240 + 120 = 3360
Step 29: 3360 + 120 = 3480
Step 30: 3480 + 120 = 3600
Step 31: 3600 + 120 = 3720
Step 32: 3720 + 120 = 3840
Step 33: 3840 + 120 = 3960
Step 34: 3960 + 120 = 4080
Step 35: 4080 + 120 = 4200

So, 120*35 = 4200