$a=\frac{1}{3}+\frac{1}{4}, b=\frac{1}{5}+\frac{1}{6}+\frac{1}{7}$, then among $a$ and $b$, the larger number is $\qquad$
【Analysis and Solution】
Fraction calculation and comparison of sizes.
$$
a-b=\left(\frac{1}{3}+\frac{1}{4}\right)-\left(\frac{1}{5}+\frac{1}{6}+\frac{1}{7}\right)=\left(\frac{1}{3}-\frac{1}{6}\right)+\frac{1}{4}-\frac{1}{5}-\frac{1}{7}=\left(\frac{1}{4}-\frac{1}{5}\right)+\left(\frac{1}{6}-\frac{1}{7}\right)>0 \text {; }
$$
$a>b$, that is, the larger number is $a$.