There are numerous ways to solve and simplify a math problem.
A simple math division can also be done differently, mentally or otherwise.
It boils down to selecting the appropriate approach.
It also depends on one's preference in solving the math question, and one's confident level.
To review another mental division focusing on the numerator, click this link for information.
The mental methods focusing on the denominator are listed below.
Number divided by 4: y / 4 ==> Do y / 2 twice ==> y/2 and y/2
Number divided by 5: y / 5 ==> Do y times 2, followed by divide by 10. Actually 2y / 10 = y / 5
Number divided by 6: y / 6 ==> Do y / 3 followed by y / 2
Number divided by 8: y / 8 ==> Do y / 3 thrice since 2 x 2 x 2 = 8
Number divided by 9: y / 9 ==> Do y / 3 twice since 3 x 3 = 9
The strategy for this mental math division is to break down the denominator to its lowest factor and perform the operation a number of times.
You may based on the knowledge that dividing by, example, 2 is simpler than dividing straight from 8, which being a bigger number, is harder to handle.
The concept of this multiple simpler division makes mental division easier and less stressful.
If possible involve the use of the number 10 which everyone should find easy to manipulate in the mind.