Answer:
4 more pens
Explanation:
Well, what do we know?
We know Sheila has:
6 pens
10 pencils
How many MORE pens does she need to make the number of pens equal to the number of pencils?
6 + x (x is the number of pens needed to EQUAL to 10)
6 + x = 10
x = 4
Sanity check:
6 + 4 = 10
Sheila needs 4 more pens to make the number of pens and pencils equivalent, or EQUAL TO each other.