One option (that I would use):
Ignore the decimals and multiply 13 x 916.
9 1 6
x 1 3
2 7 4 8
9 1 6 0
1 1 9 0 8
OK, now take into account there were a total of three digits to the right of decimal points (3, 1, and 6), so your answer also needs three digits to the right of your decimal point.
Answer 11.908
