The number is 90.
To be a multiple of 4, 10 and 20 the number must be a multiple of their lowest common multiple. lcm(4, 10, 20) = 20 What is required is a multiple of 20 between 61 and 107. The numbers 80 and 100 both satisfy the problem of being between 61 and 107 and being a multiple of 4, 10 and 20.
90
90
It is: 80
98
90
It is: 80
Just 90
80
The number is 80
80 adn 100