(1) (2)
(1) (+)(+)=+(+)+
2357
 =37=21
 10
 (+ )10=(35+72)10=290
 100=52100=1000
 =1311
 10 100
 (2)(+)=+2+
 (58)=8+28510+5=64+800+2500=3364
 +2 10+ 100
 (3) =10
 = ( )-( )
 2456=(40)-(16)=1600-256=1344