先估一估,再算一算下面各题.603+197= 700-92= 902-98= 920-111= 964-280= 430+179= 703-219= 900-361= 805-11=
(1)603+197≈800, 603+197=800; (2)700-92≈610, 700-92=608; (3)902-98≈800, 902-98=804; (4)920-111≈800, 920-111=809; (5)964-280≈700, 964-280=684; (6)430+179≈600, 430+179=609; (7)703-219≈500, 703-219=484; (8)900-361≈540, 900-361=539; (9)805-11≈790, 805-11=794. |