用竖式计算.52+34= 46+52= 34+60= 87﹣66=23+43= 27﹣16= 68﹣45= 45+24=
计算: (1)87+74+85+83+75+77+80+78+81+84 (2)1+2+3+…+24+25 (3)4×135×25.
计算. ①300﹣10﹣9.8﹣9.6﹣9.4﹣9.2﹣…﹣0.8﹣0.6﹣0.4﹣0.2 ②4.23×7.12+42.3×0.398﹣0.432×11.
(1)100﹣98+96﹣94+92﹣90+…+8﹣6+4﹣2 (2)1001×1001﹣1001.
3+6+9+…++300+3031999+999×9991.24×0.25+124×750.8888×6+0.1111×52.
计算: ①3×(x+9)=27 ②16×8﹣7x=23 ③7.5﹣7.5×0.5﹣2.6×0.8 ④13.7×6.5+5.9×13.7﹣12.4×3.7 ⑤50×[(0.2+4.8﹣4.8+0.2)÷2] ⑥11.25+21.25+31.25+41.25+51.25+61.25+71.25+81.25.