№852(г,д,е) г)3/49+5/7+4/49= д)7/10+2/15+11/30= е)1/12+1/18+1/12=

1) ( 3/49 ) + ( 5/7 ) + ( 4/49 ) = ( 7/49 ) + (35/49 ) = 42/49 ;
2) ( 7/10 ) + ( 2/15 ) + ( 11/30 ) = ( 21/30 ) + ( 4/30 ) + ( 11/30 ) = 36/30 =
= 1 ( 6/30 ) = 1 ( 1/5 ) ;
3) ( 1/12 ) + ( 1/18 ) + ( 1/12 ) = ( 2/12 ) + ( 1/18 ) = ( 1/6 ) + ( 1/18 ) =
= ( 3/18 ) + ( 1/18 ) = 4/18 = 2/9