Xiao Ming is 8 years old this year, and his grandfather is 7 times as old as Xiao Ming this year. After four years, how much older will grandpa be than Xiao Ming?
小明今年8岁，爷爷今年的年龄是小明的7倍，四年后，爷爷比小明大多少岁？
<gadget id="calculator">8 * 7</gadget>
<output>56</output>

<gadget id="calculator">56 - 8</gadget>
<output>48</output>

<result>48</result>