①407-278=129;
验算:
;
②198+619=817;
;
③705+196=901;
;
④800-66=734;
;
⑤435+247=682;
;
⑥504-235=269;
;
⑦99+703=802;
;
⑧811-139=672;
.
①407-278=129;
验算:
;
②198+619=817;
;
③705+196=901;
;
④800-66=734;
;
⑤435+247=682;
;
⑥504-235=269;
;
⑦99+703=802;
;
⑧811-139=672;
.