[求助]数学一道题目

    if n denotes a number to the left of 0 on the numberline suchi that the square of n is less than 1/100,  then the reciprocal of n must be? 

   这题目答案是less than －１０，虽然可以猜出答案，但是不太明白意思，要怎么理解呢？

　谢谢高人指点＾＿＾

　还有一题目说　　before being simplified the instruction for computing income tax were add 2 percent of one's annual income to the averange of 100 units of currency and one percent of annual income, so what;s the formula?assume the annual income is Ｉ

答案是　　５０＋Ｉ／４０　　　怎么理解呢？好困惑啊～～～

第一题:N 是负数,N的平方小于1/100,所以N的范围在-1/10..1/10之间,又因为N 是负数,所以N 只能大于-1/10,利用不等式,1/N<-10

第二题:主要是题的意思没读明白把,,题目说,将收入的2%加到一个数中,这个数是由100和收入的1%构成,所以等式为:2%+(100+1%*I)/2,化简就出来了.