OK, let's crack this. We're given 670 and our task is to multiply it by 4. Essentially, we'll be adding 670 to itself 4 times.
Step 1: 0 + 670 = 670
Step 2: 670 + 670 = 1340
Step 3: 1340 + 670 = 2010
Step 4: 2010 + 670 = 2680

So, 670*4 = 2680