Alright, let's solve this math problem step by step. First, we have the number 40. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 16. So, we're going to take the number 40 and add it to itself 16 times.
Step 1: 0 + 40 = 40
Step 2: 40 + 40 = 80
Step 3: 80 + 40 = 120
Step 4: 120 + 40 = 160
Step 5: 160 + 40 = 200
Step 6: 200 + 40 = 240
Step 7: 240 + 40 = 280
Step 8: 280 + 40 = 320
Step 9: 320 + 40 = 360
Step 10: 360 + 40 = 400
Step 11: 400 + 40 = 440
Step 12: 440 + 40 = 480
Step 13: 480 + 40 = 520
Step 14: 520 + 40 = 560
Step 15: 560 + 40 = 600
Step 16: 600 + 40 = 640

So, 40*16 = 640