`(12,48 : 0,5 × 6,25 × 4 × 2)/(2 × 3,12 × 125 : 0,25 × 10)`
`= (12,48 × 2 × 6,25 × 4 × 2)/(2 × 3,12 × 125 × 4 × 10)`
`= (12,48 × 6,25 xx 2)/(3,12 xx 125 xx 10)`
`= (3,12 xx 4 xx 6,25 xx 2)/(3,12 xx 125 xx 10)`
`= (4 xx 5 × 1,25 xx 2)/(1,25 × 100 × 10)`
`= (4 × 5 × 2)/1000`
`= 40/1000`
`= 1/25`