( 2/7 kali 21/25 )+(12/5 : 10)=

(2/7 x 21/25) +(12/5 : 10)
= 42/175 +12/50
= 84/350 +84/350
= 168/350
= 24/50
= 12/25

Itu jawabannya.

(2/7 x 21/25) = 42/175 
(12/5 : 10) = (12/5 x 1/10) = 12/50
42/175 + 12/50 = 84/350 + 84/350 = 168/350 = 24/50 = 12/25