1. Given $a+3=3a, b+4=4b, c+5=5c, d+6=6d$, then $a \times b \times c \times d=$
【Answer】3
【Analysis】The equation + fraction calculation can find $a=\frac{3}{2}, b=\frac{4}{3}, c=\frac{5}{4}, d=\frac{6}{5}$, then $a \times b \times c \times d=\frac{3}{2} \times \frac{4}{3} \times \frac{5}{4} \times \frac{6}{5}=3$.