45*55+46*54+47*53+48*52+49*51=?
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45*55+46*54+47*53+48*52+49*51=?
45*55+46*54+47*53+48*52+49*51=
=(50-5)(50+5)+(50-4)(50+4)+(50-3)(50+3)+(50-2)(50+2)+(50-1)(50+1)
=2500*5-25-16-9-4-1
=12500-55
=12445
=(50-5)(50+5)+(50-4)(50+4)+(50-3)(50+3)+(50-2)(50+2)+(50-1)(50+1)
=2500*5-25-16-9-4-1
=12500-55
=12445
45*55+46*54+47*53+48*52+49*51=?
46、47、48、49、50、51、52、53、54、55
45 46 47 48 49 50 51 52 53 54 55用简便计算怎样做
第46,47,48,49,50,51,52,53,54,55,56,57
谁有星海镖师46,47 ,48,49,50,51,52,53,54,55
用简便方法计算49+51+53+47+48+50+49+52+46+51+54+55+51+53+47+50+49+51
找规律算一算49+53+47+48+51+54+52+46=
46+47+48+49+50+51+52+53+54= ( )乘( )等于( )
50×50+49×51+48×52+47×53+46×54=?如何巧算
期末小状元五年级上册数学43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,
35+36-37-38+39+40-41-42+43+44-45-46+47+48-49-50+51+52-53-54+
46 47 48 49 51 52 54 55 57课的题目