56/25*65/34*51/52

21/5

Reason (quick cancellation):

• 56 = 2^3·7, 65 = 5·13, 51 = 3·17
• 25 = 5^2, 34 = 2·17, 52 = 2^2·13
• Cancel 2^3 with 2^3, one 5 with 5^2, 13, and 17
• Left with numerator 3·7 = 21 and denominator 5

So the product equals 21/5 = 4.2 = 4 1/5.