7.680/ 15 is about 46.

8.80-45.6=34.4 yuan, and 34.4/2.5 is about 13.

9.450/ 16 is approximately equal to 28 cups 9 * 28 = 252g, and 252g is approximately equal to 0.25kg 。

10.6.3/7=0.9 ton 0.9*5*3 1= 139.5 ton.

I hope my answer can help you, and I wish you success in your studies.