OK, let's work through this together. We're starting with 901 and we're going to multiply it by 7, which means we add 901 to itself 7 times.
Step 1: 0 + 901 = 901
Step 2: 901 + 901 = 1802
Step 3: 1802 + 901 = 2703
Step 4: 2703 + 901 = 3604
Step 5: 3604 + 901 = 4505
Step 6: 4505 + 901 = 5406
Step 7: 5406 + 901 = 6307

So, 901*7 = 6307