請問一題國中數學.........?

1 / (1/991 + 2/991 + 3/991 + 4/991 + 5/991 + 6/991) < 1 / (1/991 + 2/992 + 3/993 + 4/994 + 5/995 + 6/996)
1 / ( (1+2+3+4+5+6)/991 ) < 1 / (1/991 + 2/992 + 3/993 + 4/994 + 5/995 + 6/996)
991/21 < 1 / (1/991 + 2/992 + 3/993 + 4/994 + 5/995 + 6/996)
;
1 / (1/991 + 2/992 + 3/993 + 4/994 + 5/995 + 6/996) < 1 / (1/996 + 2/996 + 3/996 + 4/996 + 5/996 + 6/996)
1 / (1/991 + 2/992 + 3/993 + 4/994 + 5/995 + 6/996) < 996/21
∴
991/21 < 1 / (1/991 + 2/992 + 3/993 + 4/994 + 5/995 + 6/996) < 996/21
47 + 4/21 < 1 / (1/991 + 2/992 + 3/993 + 4/994 + 5/995 + 6/996) < 47 + 9/21
1 / (1/991 + 2/992 + 3/993 + 4/994 + 5/995 + 6/996) 的整數部分是 47.