2,5:1dua per 3:2satu per4 dikali4,5dikurang27persembilan

= 25/10 × 6/3 : 9/4 × 45/10 - 27/9
= 25/10 × 6/3 × 4/9 × 45/10 - 27/9
= 5 × 4 × 5/10 - 3
= 2 × 5 - 3
= 10 - 3
= 7