小学数学五年级上册课件整数乘法运算定律推广到小数21已翻译ppt

?uli?S PGPt?rPa?li5-?SiiSa PoSrPtSrPt 1-?S1S?i aiP1?Si?Sral?o?ltlG?iSi?iP?ii?G l S1lo?Sral?o?Si?Sral?G?r?PtuPG?i?iP?ab=ba?Si?Sral?aS?i?iP?(ab)c=a(bc)?Si?Sral?SrS?Pr?i?iP?(a+b)c=ac+bc?SraP?Pi?o?itSiS?olr 0.71.21.20.7（0.80.5）0.40.8（0.50.4）（2.43.6）0.52.40.53.60.5 l?S?oS?S?i liS?P?SG?SiSo?SiSG?liS?iStSi?SrS?o?S?S?S砀aP?a?itSiS?S砀rlr?SiS?0.71.21.20.7（0.80.5）0.40.8（0.50.4）（2.43.6）0.52.40.53.60.5?Si?Sral?o?G?r?PtuPG?i?iP?Si?Sral?o?aS?i?iP?Si?Sral?o?SrS?Pr?i?iP?595?riar?r?9?1i?1i19?r1r?a?1i1?r1r?9?i?9?r1r?1ir?ri?i?1?9?a?l?1r?il?.0.25 0.254.784.784 4 a1?砐P1?SiSo?SiSG?liS?a?SiSia?G?iP?P1Si?P1S?PG?Su?=0.25 =0.254 44.784.78?Si?Sral?G?r?PtuPG?i?iP?=14.78 =4.78 0.65201 a1?砐P1?SiSo?SiSG?liS?a?SiSia?G?iP?P1Si?P1S?PG?Su?=0.652000.651?Si?Sral?o?SrS?Pr?i?iP?=0.65（2001）=130.65?SraP?161.25 a1?砐P1?i a?Si?lG?a?SrSiS?SG?iP?P1Si?P1S?S?砐?t?砐?PG?Su?SitSo?PrSia?G?u?1?G?lG?o.161.25 a1?砐P1?i a?Si?lG?a?SrSiS?SG?iP?P1Si?P1S?S?砐?t?砐?PG?Su?SitSo?PrSia?G?u?1?G?lG?o.161.25=(28)1.25=2（81.25）=210=20 a1?砐P1?i a?Si?lG?a?SrSiS?SG?iP?P1Si?P1S?S?砐?t?砐?PG?Su?SitSo?PrSia?G?u?1?G?lG?o.(3+5)0.8 a1?砐P1?i a?Si?lG?a?SrSiS?SG?iP?P1Si?P1S?S?砐?t?砐?PG?Su?SitSo?PrSia?G?u?1?G?lG?o.（3+5）0.8=30.8+50.8=2.4+4=6.4 a1?砐P1?i a?Si?lG?a?SrSiS?SG?iP?P1Si?P1S?S?砐?t?砐?PG?Su?SitSo?PrSia?G?u?1?G?lG?o.=（3+5）0.8=80.8=6.4 (3+5)0.8?SraP?5?19?riar?r?9?ir?1ir?r1r?ri?i?1?9?a?l?1r?il?r?r?9?ir?r?r1r?r?i?1ir?ri?i?r?9?r?a?i?i19?a?rr?1r?.?SirlGP1?Sr1?l1?i?iS?S?G?PiS1?S砀!1.?i1r?92.52.5(0.77(0.770.4)=0.4)=6.16.13.6+3.93.6+3.93.6=(+)3.6=(+)2.028.5=8.5+8.5 48480.25=0.250.25=0.25 0.770.42.523.63.96.11240.22.?ii?m?m9?0.20.20.6=0.30.6=0.30.40.4?Si?Sral?G?r?PtuPG?i?iP?（）4.9+4.94.9+4.94.9=4.94.9=4.9(1+4.9)(1+4.9)()5.6+5.6+2.45.6+5.6+2.45.6=5.65.6=5.6(5.6+2.4)(5.6+2.4)()()3.?PG?u?1?G?iSrSi?P1S?iS SiiPrS?Su?S?PG?u?1?G?a?P1S?tl?1aP?ltlG?iSi?iP?iS?S砀SiiPriau?SraG?S .（1）1.251780 0.681013.652.83.657.25.4199 =1.258017 =10017=1700 =（2.8+7.2）3.65 =103.65 =36.5 =0.68（100+1）=0.68100+0.681 =68+0.68=68.68 =5.4（200-1）=5.4200-5.41 =1080-5.4=1074.6?SraP?.?r?6?i5?9?4 （4 4）0.80.80.50.51.251.250.40.4 =(0.8 =(0.81.25)+(0.51.25)+(0.50.4)0.4)=1+0.2 =1+0.2=1.2=1.2 (2)12.5(2)12.52.52.53.23.2 =12.5 =12.52.52.5(8(80.4)0.4)=12.5 =12.58+2.58+2.50.40.4 =100+1 =100+1=101=101（1 1）98986.5 6.5 =(98+2)=(98+2)6.5 6.5 =100 =1006.5 6.5 =650=650 （3 3）0.960.96201 201 =0.96 =0.96200+1 200+1 =192+1 =192+1 =193=193?Sr l?Sr l?G?Sr l?:?Sr l?G 在日常生活中，随处都可以看到浪费粮食的现象。也许你并未意识到自己在浪费，也许你认为浪费这一点点算不了什么在日常生活中，随处都可以看到浪费粮食的现象。也许你并未意识到自己在浪费，也许你认为浪费这一点点算不了什么5.?rr?a?rr?rr1?a?.9.8+999.84.6532+2.546.5+0.465430=9.8（99+1）=9.8100=980=4.6532+254.65+4.6543=（32+25+43）4.65=1004.65=4656.?r?i?1?1?.2.2.?u PPr 25 25?S?la?SitS?SG?u砐Sr1?S?1.7 1.7?a?S lroS?la 8 8?P?P1u?Gtl l?iP?o?Su?PrS?P?Si a?S So?SiSrSiS?SiS1 S 4.5 4.5?a?PuiSa?SiSrSi?SiS1 S 2.52.5?a?a?rSiS?砐 aSuP?SrSiS?S 12 12?S?P1u砐Sr1?Gtl l?iP?Sro （1）4.512+2.512 =54+30 =84（?a）（2）（）（4.5+2.5）12 =7 12 =84（?a）（1）1.78 25 =13.625 =340（?a）（2）2581.7 =2001.7 =340（?a）?SraP?1i1?9ia?r?6?i19?ar1i1?r?9?rl?iaiai?.4 4?0.80.8?1.251.25?S?PG?G?P1?P?Si?Sral?o?ltlG?S?Si?iP?SiSiS?aP?P?SG?r?lt?ltlG?iSi?iP?iP?P1iau?PG?iSrSi?P1S?iS砀SiiPrS?Su?SraG?S .?liS1lt 0.841.25 =0.81.254 =14=4?SraP?