Let's roll up our sleeves and solve this. We have 240 and we're going to multiply it by 18, essentially adding 240 to itself 18 times.
Step 1: 0 + 240 = 240
Step 2: 240 + 240 = 480
Step 3: 480 + 240 = 720
Step 4: 720 + 240 = 960
Step 5: 960 + 240 = 1200
Step 6: 1200 + 240 = 1440
Step 7: 1440 + 240 = 1680
Step 8: 1680 + 240 = 1920
Step 9: 1920 + 240 = 2160
Step 10: 2160 + 240 = 2400
Step 11: 2400 + 240 = 2640
Step 12: 2640 + 240 = 2880
Step 13: 2880 + 240 = 3120
Step 14: 3120 + 240 = 3360
Step 15: 3360 + 240 = 3600
Step 16: 3600 + 240 = 3840
Step 17: 3840 + 240 = 4080
Step 18: 4080 + 240 = 4320

So, 240*18 = 4320