Solve these fraction multiplication problems: 1) 12/4 16/12 4/8 2) 12/6 15/12 12/4

$$\frac{12}{4} \times \frac{16}{12} \times \frac{4}{8}$$

Cancel 12 (numerator of the first fraction) and 12 (denominator of the second fraction): $12 \div 12 = 1$.
The expression becomes:

$$\frac{1}{4} \times \frac{16}{1} \times \frac{4}{8}$$

Cancel 16 (numerator of the second fraction) and 4 (denominator of the first fraction): $16 \div 4 = 4$, $4 \div 4 = 1$.
The expression becomes:

$$\frac{1}{1} \times \frac{4}{1} \times \frac{4}{8}$$

Cancel 4 (numerator of the second fraction) and 8 (denominator of the third fraction): $4 \div 4 = 1$, $8 \div 4 = 2$.
The expression becomes:

$$\frac{1}{1} \times \frac{1}{1} \times \frac{4}{2}$$

Simplify $\frac{4}{2}$ to $\frac{2}{1}$.

$$\frac{1}{1} \times \frac{1}{1} \times \frac{2}{1}$$

$$\frac{1 \times 1 \times 2}{1 \times 1 \times 1} = \frac{2}{1} = 2$$

The final answer is $\boxed{\text{2}}$.

: $\frac{12}{6} \times \frac{15}{12} \times \frac{12}{4}$

$$\frac{12}{6} \times \frac{15}{12} \times \frac{12}{4}$$

Cancel 12 (numerator of the first fraction) and 12 (denominator of the second fraction): $12 \div 12 = 1$.
The expression becomes:

$$\frac{1}{6} \times \frac{15}{1} \times \frac{12}{4}$$

Cancel 15 (numerator of the second fraction) and 6 (denominator of the first fraction) by dividing by 3: $15 \div 3 = 5$, $6 \div 3 = 2$.
The expression becomes:

$$\frac{1}{2} \times \frac{5}{1} \times \frac{12}{4}$$

Cancel 12 (numerator of the third fraction) and 4 (denominator of the third fraction): $12 \div 4 = 3$, $4 \div 4 = 1$.
The expression becomes:

$$\frac{1}{2} \times \frac{5}{1} \times \frac{3}{1}$$

$$\frac{1 \times 5 \times 3}{2 \times 1 \times 1} = \frac{15}{2}$$

The final answer is $\boxed{\frac{15}{2}}$.