Odd numbers greater than 1 on a number cube are 3 and 5. The probability of rolling one of those two numbers is 2 out of 6 (2/6), which can be simplified to 1/3 by dividing both the numerator and denominator by 2.
If he rolls the cube 78 times and every time there is a 1/3 chance of rolling 3 or 5, then to calculate how many times he can expect to roll those numbers, we must multiply 78/1 by 1/3.
78/1 x 1/3 = 78/3
78/3 = 26
He can expect to roll an odd number greater than one 26 times.