Let's roll up our sleeves and solve this. We have 151 and we're going to multiply it by 4, essentially adding 151 to itself 4 times.
Step 1: 0 + 151 = 151
Step 2: 151 + 151 = 302
Step 3: 302 + 151 = 453
Step 4: 453 + 151 = 604

So, 151*4 = 604