Mrs Singh bought 9 folders 9 notebooks. The cost of each folder is $2.50 and the cost of each notebook is $4 write two equivalent expressions then find the answer

First you add250+250 then you add 9+9 or you could do250*9 2 times then add them together. never mind just do 250*9 2times and that will eqaul 2,250 then add 2250 + 2250and you got the answer and the answer is 4500