a)
23/69 + 12/36 + 18/58 = 1/3 + 1/3 + 9/29 = 2/3 + 9/29 = 58/87 + 27/87 = 85/87
b)
10/26 + 18/12 + 24/39 + 5/10 = 5/13 + 3/2 + 8/13 + 1/2 =
= (5/13 + 8/13) + ( 3/2 + 1/2) =
= 13 /13 + 4/2 =
= 1 + 2 =
= 3
c)
(1 × 2 × 4 )/3 + ( 4 ×3 ) ×5 / 3 ² + ( 2 ×3 × 5) / ( 2² × 3²) =
= 8/3 + 20/3 + 5/ 6 =
= 16/6 + 40/6 + 5/6 =
= 61/60 =
= 1 intreg si 1/60