56.7一3.8=52.9或52.9十3.8=567
解:56.7-3.8=52.9验算:52.9+3.8=56.7
56.7-3.8=52.9验算:52.9+3.8=56.7或:56.7-52.9=3.8
56.7-3.8=52.9验算52.9+3.8=56.7
56.7-3.8=52.952.9+3.8=56.7