求未知数x.0.9x+=0.8x+2.510:(x+1)=4.5:0.8.
计算(能简算的要简算)10.1×27 13.7×6.1+3.9×13.7 87.5×0.05×2.
用简便方法计算.63+8.7+8.7×3.7 (﹣+)×12.
用简便方法计算①0.4×1.36×2.5 ②0.45×101 ③3.8×4.6+4.6×6.2.
怎样简便就怎样计算:2.9×1.4+2×0.16 5.4×2.08+66×0.208﹣2.0830.8÷[14﹣(9.85+1.07)][(12.5+1.25+0.125)×80﹣999]÷0.03.
简便计算(1)2999×23+23 (2)469﹣(175+69) (3)808﹣156﹣144(4)301×31﹣31 (5)54×102 (6)88×125.