Without delay, let's solve this. We've got 870 and we will be multiplying it by 5, that is, adding 870 to itself 5 times.
Step 1: 0 + 870 = 870
Step 2: 870 + 870 = 1740
Step 3: 1740 + 870 = 2610
Step 4: 2610 + 870 = 3480
Step 5: 3480 + 870 = 4350

So, 870*5 = 4350