Let's get this math done. We have 631 and we're going to multiply it by 20. This is the same as taking 631 and adding it to itself 20 times.
Step 1: 0 + 631 = 631
Step 2: 631 + 631 = 1262
Step 3: 1262 + 631 = 1893
Step 4: 1893 + 631 = 2524
Step 5: 2524 + 631 = 3155
Step 6: 3155 + 631 = 3786
Step 7: 3786 + 631 = 4417
Step 8: 4417 + 631 = 5048
Step 9: 5048 + 631 = 5679
Step 10: 5679 + 631 = 6310
Step 11: 6310 + 631 = 6941
Step 12: 6941 + 631 = 7572
Step 13: 7572 + 631 = 8203
Step 14: 8203 + 631 = 8834
Step 15: 8834 + 631 = 9465
Step 16: 9465 + 631 = 10096
Step 17: 10096 + 631 = 10727
Step 18: 10727 + 631 = 11358
Step 19: 11358 + 631 = 11989
Step 20: 11989 + 631 = 12620

So, 631*20 = 12620