第1讲方阵问题ppt.ppt
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上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool第第1讲讲方阵问题方阵问题三年级第二学期三年级第二学期上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool方阵是由人或物排成的正方形,一般有实心(图1)和空心(图2)两种形式。
图图1图图2上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolACDB上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool二层中空方阵二层中空方阵CBA4444实心方阵实心方阵一层中空方阵一层中空方阵上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool实心方阵总数实心方阵总数=每边数每边数每边数每边数4444实心方阵实心方阵5555实心方阵实心方阵上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool一层中空方阵一层中空方阵上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool544=16上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool(52)44=16上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool52(52)2=16上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool5533=16上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool(51)4=16上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool方方阵阵557788nn每边数每边数每层总数每层总数n(n-1)4516724828每层总数每层总数=(每边数(每边数-1)4每边数每边数=每层总数每层总数4+1上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool例例1:
某小学学生排成某小学学生排成20个人一行的个人一行的正方形方阵,这个小学一共有多少学正方形方阵,这个小学一共有多少学生?
最外层共站多少学生?
生?
最外层共站多少学生?
2020=400(人)(20-1)4=76(人)答:
答:
这个小学一共有这个小学一共有400名学生。
最名学生。
最外层共站多少外层共站多少76人。
人。
上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool每边数每边数每边总数每边总数最外层最外层向里一层向里一层再向里一层再向里一层每向里一层,每边数每向里一层,每边数减少(减少(),每边),每边总数减少(总数减少()。
)。
2288上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool(11-1)4=40(人)40-8=32(人)答:
答:
这个小学一共有这个小学一共有40名学生。
最名学生。
最外层共站多少外层共站多少72人人。
练一练练一练11:
某校四年级学生正好排成一个实:
某校四年级学生正好排成一个实心方阵的队形,最外层每边上有心方阵的队形,最外层每边上有1111人,最外人,最外层一共有多少人?
最外层一共有多少人?
最外22层一共有多少人?
层一共有多少人?
40+32=72(人)上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchoolShanghaiFushanForeignLanguagePrimarySchool例例2:
六一节团体操方阵,最外层一共:
六一节团体操方阵,最外层一共有有44人,最外层每边有多少名学生?
人,最外层每边有多少名学生?
整个方阵一共有多少人?
整个方阵一共有多少人?
444+1=12(人)1212=144(人)答:
答:
最外层每边有12名学生,整个方阵一共有144人。
上海福山外国语小学上海福山外国语小学上海福山外国语小学上海福山外国语小学ShanghaiFushanForeignLanguage