“(a+68)+32=a+(68+32)”,此等式所应用的运算定律是 ( )
(475+666)+525=666+(475+525)运用了加法结合律和交换律.
▲+(●+b)=(▲+●)+ b
285+374=374+285________
86+75+25=86+(75+25)________
48+27+52+73=(48+52)+(27+73) ________
27+45+73=27+73+45________
155+129+45
85+313 42+87+58 (73+64)+37 56+78+44 (206+189)+294 |
(73+37)+64 189+(206+294) 313+85 87+(42+58) 78+(56+44) |