8 - (7 1/2-3 1/3)*9/10

Question

8 - (7 1/2-3 1/3)*9/10

Answer 1

8-(7 1/2-3 1/3)*9/10=
7 1/2-3 1/3=4 1/6
4 1/6*9/10=3 3/4
8-3 3/4=5*4/4-3/4=17/4=4 1/4

Comments

откуда появилось 4/4?