In order to score 2 or lower, students must score either 1 or 2.
These two events happen with probabilities 0.12 and 0.34, respectively, which means with probability [tex] 0.12+0.34 = 0.46 [/tex] a student will score 2 or less.
You may read this as "46% of students score 2 or less"
So, out of 1000 students, we expect
[tex] 1000 \cdot \dfrac{46}{100} = 460 [/tex]
students to score 2 or less.