小数加减法思维题

5.74D2.42D3.26D4.5819.9D19.98D19.997U19.99960.8D0.9DDDDDDDDDDDDDDDDDDDDDDDDDo.1a0.2DDDDDDDDDDDDDDDaaaaaaaaaaaaa10.43DDDDDDDDD6.18aaaaaaaa6.75DDDDDDDDDDDDDDDDDDDD0.2D0.6D1.0D1.4D()D()0.6D1.8D5.4D()D()0.5D1.5D4.5D()D()1.DDDDDDDD,DDDDDDDD9DDD4,DDDDDDDDDD1DDD7DDDDDDD17.42,DDDDDDDDa?2DDDDDDDDDDDD,DDDDDDDD9DD6,DDDDDDDD4aa7DDDDDDDDD15.4,aaaaaaaaaaa?3.DDDDDDDDDDDDDDDDDDDD3DDD8,DDDDDDDD7DDD2DDDDDDDDDD1.87,ODDDDDDDDDDD?4.DDDDDDDDDD,DDDDDDDDDDDDDDDDDDDDaaaaDDDDDD2aaa6,aa7aaaiaDDDDDDDDDDDDDDDDDDDDDD?5DDDDDDDDDDDDDDDDDDDDDDDD4DDD9DDDDDDDDD9DDD4 叽DDDDDDDDDDDDDDDDDDD6DDDDDDDDDDD1.27DD1.35DDDDDDDDDDDDDDDDaaaa0.25a,aaaDDDDDD?7DDDDDDDD12.65DD,DDDDD,DDDa6.85aa,aaaaaDDDDDD?8DDDDDDDDDDDDDDDDD,aaaDDDDDDDDDDDDDDDDDDDDDDa,DDDDDD()DDDDDDDDDDDa,aaaa()；aaaDDDDDDD,aaaa()a9DDDD5DDDODDa:(i)aaODDDD(2) DDDD0.(3) aaoaaa10DDDDDDDDDD◎DD5DDDDDDDDDDDDDDD4.9D,DDDDDDDDDDDDaaaa9.8aaaaaDDDDDDDDDD?5DDDD11DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD0.2DDDDDDDDDD1DDDD0.1DDDDDDD