316+346-489 831-558+329 470+(365-98)
106+378+294 517﹣109﹣217
906﹣351+208 291﹣21÷3
500+378-527= 900-113-287= 612-268+320=
641-117+358 467-278-129 768-(219+287)
①800-(420-150)
②247+169-221
=976-(148+52)
=976-200
=776 ( )改正:
=376-176+59
=200+59
=259 ( )改正: