Răspuns :
Notam numarul cu a
[(a x 6 + 22 ) : 7 - 4 ] x 9 = 54
(a x 6 + 22 ) : 7 - 4 = 54 : 9
(a x 6 + 22 ) : 7 - 4 = 6
(a x 6 + 22 ) : 7 = 6 + 4
(a x 6 + 22 ) : 7 = 10
a x 6 + 22 = 10 x 7
a x 6 + 22 = 70
a x 6 = 70 - 22
a x 6 = 48
a = 48 : 6
a = 8 → numarul la care m-am gandit
Verific: [ ( 8 x 6 + 22) : 7 - 4] x 9 = [ ( 48 + 22) : 7 - 4 ] x 9 = ( 70 : 7 - 4) x 9 =
= ( 10 - 4) x 9 = 6 x 9 = 54
[(a x 6 + 22 ) : 7 - 4 ] x 9 = 54
(a x 6 + 22 ) : 7 - 4 = 54 : 9
(a x 6 + 22 ) : 7 - 4 = 6
(a x 6 + 22 ) : 7 = 6 + 4
(a x 6 + 22 ) : 7 = 10
a x 6 + 22 = 10 x 7
a x 6 + 22 = 70
a x 6 = 70 - 22
a x 6 = 48
a = 48 : 6
a = 8 → numarul la care m-am gandit
Verific: [ ( 8 x 6 + 22) : 7 - 4] x 9 = [ ( 48 + 22) : 7 - 4 ] x 9 = ( 70 : 7 - 4) x 9 =
= ( 10 - 4) x 9 = 6 x 9 = 54