我会巧算.1.2×0.4+1.3×0.4 (1.25+0.36)×0.2 7.2×0.3+28×0.03 0.25×0.56×0.48×(2.5+0.125) 0.25×0.56×0.4 32.8+5.6+7.2 75.2﹣66.9﹣5.2.
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×+×.
1﹣×{1﹣×[1﹣×(1﹣)]} 55×+145×9999×9999+19999 77×13+255×999﹣510.
计算:18+19+20+21+22+23.
①1.25×460×560②2.74×198③56÷(0.25×7)④1.25×0.4+3.72×8×2.5⑤7200÷75⑥6.666×2490+2.222×2530⑦101﹣0.9﹣0.09﹣0.009﹣0.0009﹣0.00009⑧2000+1999﹣1998+1997﹣1996+1995﹣1994+…+3﹣2+1.