OK, let's crack this. We're given 158 and our task is to multiply it by 4. Essentially, we'll be adding 158 to itself 4 times.
Step 1: 0 + 158 = 158
Step 2: 158 + 158 = 316
Step 3: 316 + 158 = 474
Step 4: 474 + 158 = 632

So, 158*4 = 632