Question

the shop teacher, mr. humphrey, wrote down how many picture frames the students made last week. making picture frames how many students made at least 1 picture frame? students submit

Explanation:

Step1: Identify non - zero data

Count the number of 'x's for values 1, 2, 3, and 4.

Step2: Add the counts

For 1 picture frame, there are 4 'x's; for 2 picture frames, there is 1 'x'; for 3 picture frames, there are 2 'x's; for 4 picture frames, there are 6 'x's.
$4 + 1+2 + 6$

Answer:

13