zegroes and CPhill u all answered really very good but i also wanna answer this question so here we go :
5/4 x 9/10
=1/4 x 9/2 (here we have cut 5 and 10)
=9/8 = 1 1/8 (this is the mixed form of 9/8 , i just did for just if u need it ) =1.125 (thats the decimal form )
i gave u the answer in three forms becoz i thought u could use the one u require or ur teacher teaches u !so i just hope this helps !