Split the problem into 4 problems two for each place. Then add the products.
31 x 27:
30 x 20 = 600
30 x 7 = 210
1 x 20 = 20
1 x 7 = 7
600 + 210 + 20 + 7 = 837
The math in the image is incorrect because the user multiplied by the number in the tens places but not the full number. Any number in the tens place should be ten times the number in the tens place and not left alone as a single digit.
