4. Which number should replace the symbol * in the equation $2 \times 18 \times 14=6 \times * \times 7$ to make it correct?
A 8
B 9
C 10
D 12
E 15
4. D Write each number in the expression as a product of prime factors to obtain $2 \times 2 \times 3 \times 3 \times 2 \times 7=2 \times 3 \times * \times 7$. It can then be seen that $2 \times 2 \times 3=*$ and hence the value of $*$ is 12 .