Answers:
a. 3 : 5 = 12 : 20
12 is four times 3, so multiply 5 by 4. (5 × 4 = 20)
b. 4 : 9 = 12 : 27
27 is three times 9, so multiply 4 by 3. (4 × 3 = 12)
c. 8 : 7 = 16 : 14
14 is two times 7, so divide 16 by 2. (16 ÷ 2 = 8)
d. 2 : 3 = 3 : 4 (?)
3 is one higher than 2, so add 1 to 3. (3 + 1 = 4)
