These questions test your verbal reasoning skills. This includes your testing vocabulary, a logical approach, your ability to determine patterns within words and your ability to manipulate words.
6 + 7 = 8 + (?)
All the questions can be answered from left to right; there are no other mathematical issues to consider when answering these questions.
Working from left to right: 6 + 7 = 13 So the right hand side of the sum “8 + (?) must also equal 13.
What number do you need to add to 8 to get 13? 8 + (5) = 13 So the correct answer option is “C”, 5.
There is no variance within these questions; depending your arithmetic skills you should be aiming for 100% accuracy with these questions.