Answer:
Hai
Yes, its true.
because in 21, there are 4 times of 5 and we have left 1 number..
you can multiply -4 with 5 and add the number of the denominator (1)
i wanna give one more example because couldnt explained well.
3 2/3 can be written as 11/3.
you can try it too!
good luck(:
