Alright, let's solve this math problem step by step. First, we have the number 400. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 64. So, we're going to take the number 400 and add it to itself 64 times.
Step 1: 0 + 400 = 400
Step 2: 400 + 400 = 800
Step 3: 800 + 400 = 1200
Step 4: 1200 + 400 = 1600
Step 5: 1600 + 400 = 2000
Step 6: 2000 + 400 = 2400
Step 7: 2400 + 400 = 2800
Step 8: 2800 + 400 = 3200
Step 9: 3200 + 400 = 3600
Step 10: 3600 + 400 = 4000
Step 11: 4000 + 400 = 4400
Step 12: 4400 + 400 = 4800
Step 13: 4800 + 400 = 5200
Step 14: 5200 + 400 = 5600
Step 15: 5600 + 400 = 6000
Step 16: 6000 + 400 = 6400
Step 17: 6400 + 400 = 6800
Step 18: 6800 + 400 = 7200
Step 19: 7200 + 400 = 7600
Step 20: 7600 + 400 = 8000
Step 21: 8000 + 400 = 8400
Step 22: 8400 + 400 = 8800
Step 23: 8800 + 400 = 9200
Step 24: 9200 + 400 = 9600
Step 25: 9600 + 400 = 10000
Step 26: 10000 + 400 = 10400
Step 27: 10400 + 400 = 10800
Step 28: 10800 + 400 = 11200
Step 29: 11200 + 400 = 11600
Step 30: 11600 + 400 = 12000
Step 31: 12000 + 400 = 12400
Step 32: 12400 + 400 = 12800
Step 33: 12800 + 400 = 13200
Step 34: 13200 + 400 = 13600
Step 35: 13600 + 400 = 14000
Step 36: 14000 + 400 = 14400
Step 37: 14400 + 400 = 14800
Step 38: 14800 + 400 = 15200
Step 39: 15200 + 400 = 15600
Step 40: 15600 + 400 = 16000
Step 41: 16000 + 400 = 16400
Step 42: 16400 + 400 = 16800
Step 43: 16800 + 400 = 17200
Step 44: 17200 + 400 = 17600
Step 45: 17600 + 400 = 18000
Step 46: 18000 + 400 = 18400
Step 47: 18400 + 400 = 18800
Step 48: 18800 + 400 = 19200
Step 49: 19200 + 400 = 19600
Step 50: 19600 + 400 = 20000
Step 51: 20000 + 400 = 20400
Step 52: 20400 + 400 = 20800
Step 53: 20800 + 400 = 21200
Step 54: 21200 + 400 = 21600
Step 55: 21600 + 400 = 22000
Step 56: 22000 + 400 = 22400
Step 57: 22400 + 400 = 22800
Step 58: 22800 + 400 = 23200
Step 59: 23200 + 400 = 23600
Step 60: 23600 + 400 = 24000
Step 61: 24000 + 400 = 24400
Step 62: 24400 + 400 = 24800
Step 63: 24800 + 400 = 25200
Step 64: 25200 + 400 = 25600

So, 400*64 = 25600