Hello!
For #1, the LCD is (A) 12 since both numbers go into 12 as their minimal number.
For #2, the missing number is (B) 4 because 1/4*4/4=4/16.
For #3, the answer is (B) 3 because you have to crossmultiply 20n(4*15) to find the answer.
for #4, the correct answer is (A) 4/5 is less than 5/6 because when converted into fractions with a common denominator, 24/30 is less than 25/30.
For #5, the LCD is 36; therefore, the answer is (A) because the fractions in the answer are properly converted to their new denominator.
I really hope I helped!