FREE 6th Grade PSSA Math Practice Test - Effortless Math Common Core Mathematics Workbook For Grade 6 Step-By-Step Guide to Preparing for the Common Core Math Test 2019 Download $ 18.99 $ 13.99 Rated 4.53 out of 5 based on 170 customer ratings Answers: 1- D First, we need to find the GCF (Greatest Common Factor) of 143 and 55. \ (143=11×13\) \ (55=5×11→\) GFC\ ( = 11\) Therefore, we need 11 boxes. 2- C