Let's roll up our sleeves and solve this. We have 835 and we're going to multiply it by 13, essentially adding 835 to itself 13 times.
Step 1: 0 + 835 = 835
Step 2: 835 + 835 = 1670
Step 3: 1670 + 835 = 2505
Step 4: 2505 + 835 = 3340
Step 5: 3340 + 835 = 4175
Step 6: 4175 + 835 = 5010
Step 7: 5010 + 835 = 5845
Step 8: 5845 + 835 = 6680
Step 9: 6680 + 835 = 7515
Step 10: 7515 + 835 = 8350
Step 11: 8350 + 835 = 9185
Step 12: 9185 + 835 = 10020
Step 13: 10020 + 835 = 10855

So, 835*13 = 10855