□△*△□=?
The product of the 2-digit numbers above is the 3-digit number □◇□, where △,◇and□ are three different nonzero digits. If △*□ <10, what is the 2 -digit number □△?
A) 11
B) 12
C) 13
D) 21
E) 31
為甚麼答案是21啊? 我選11說
-- by 会员 wealthylun (2012/2/5 21:22:19)