jadikan ke pecahan biasa 15%×2,5-3/10:0,5

15% = 15/100
2,5 = 25/10
3/10 = 3/10
0,5 = 5/10
15/100 × 25/10 - 3/10 : 5/10 =

15% × 2,5 - 3/10 : 0,5
= 15/100 × 25/10 - 3/10 : 1/2
= 3/20 × 5/2 - 3/10 × 2
= 15/40 - 6/10
= 15/40 - 24/40
= - 9/40