1. Problema 1
1. ¿Cu´ntos n´meros de tres cifras abc ( a = 0 ) cumplen
a u
que a es distinto de b y b es distinto de c? (ONEM
2006)
2. Los n´meros 1447 , 1005 y 1231 tienen algo en com´n.
u u
Each is a four-digit number beginning with that has ex-
actly two identical digits. How many such numbers are
there?
3. dfdfg
4. dfdf df fggf fgbb ffgb nn fgbfg bhnyn tnn ynty tynn fbnfb
1

2. frhrb frbb fgb gfb
5. ddf dgdfgdf dfd x + 2 + 3 + 4 + 4 + 555 + x2 = 8
sdfsfs sdssdfsfreggedg sdfdg sdfsdf sdfsdf sdsdfsf sfsfsdfs-
dfsf sdfsdf
2