小学五年级奥数练习及部分答案--4小数的巧算--巧算（四）

(3)3.14×6.5+4.5×3.14-3.14

(4)1240×3.8+124×51+1.24×1400+760×9.6+0.76×700

例63、用简便方法计算下列各题 (1)0.1949×19991999-0.1999×19491949

(2)199.5×199.4-199.1×199.8

(3)41.2×8.1+11×9.25+537×0.19

例64、计算

(1)36×34 (2)63×43

(3)103×106 (4)102×98

(5)33332 (6)6.3×6.7

(7)5.42 (8)7.348×11

(9)1.14 (10)1.02×1.03

(11)10.4×9.6 (12)6.542-3.462

例65、0.1+0.3+0.5+…+0.9+0.11+0.13+0.15+…+0.99

例66、计算下列各题

(1)15×11.1÷3.75÷3.7 (2)1.44÷1.56×13

(3)3.7×2.2+3.9×7.4 (4)8.4×147.75+2.1×409

(5)1.94×1.95-1.91×1.98 (6) 11.1×4÷9×3÷7.4×2

(7)7142.85÷3.7÷2.7×1.7×0.7

(8)4.83×0.59+0.41×1.59-0.324×5.9

(9)99×1.01×77.78+66.66×33.33

(10)37.4×2.7+499×0.73+12.5×0.7

例67、用简便方法计算

(1)4.7×4.3 (2)7.4×3.4

(3)9.3×10.7 (4)9.372-5.632

(5) 7.52 (6)1.05×1.07

(7) 99.992 (8)3.33332

例68、计算下列各题

(1)1.1+2.2+3.3+4.4+5.5+6.6+7.7+8.8+9.9

(2)0.1+0.2+0.3+…+0.9+0.10+0.11+0.12+…+0.99

(3)6.11+9.22+8.33+7.44+3.55+4.66+5.77+2.88+1.99

(4)3.1416×252-3.1416×152