OK, let's work through this together. We're starting with 75 and we're going to multiply it by 7, which means we add 75 to itself 7 times.
Step 1: 0 + 75 = 75
Step 2: 75 + 75 = 150
Step 3: 150 + 75 = 225
Step 4: 225 + 75 = 300
Step 5: 300 + 75 = 375
Step 6: 375 + 75 = 450
Step 7: 450 + 75 = 525

So, 75*7 = 525