Question

professor martin looked at the scores from the last quiz. scores on the last quiz how many students are there in all? students

Explanation:

Step1: Count the number of X's for each score

For score 5: 6 X's.
For score 6: 7 X's.
For score 7: 3 X's.
For score 8: 2 X's.
For score 9: 5 X's.
For score 10: 12 X's.

Step2: Sum up the number of X's

$$6 + 7+3 + 2+5 + 12$$
$$=(6 + 7)+(3 + 2)+(5 + 12)$$
$$=13+5+17$$
$$=18 + 17$$
$$=35$$

Answer:

35