用简便方法计算下列各题. 137+86+63 254+(524+146) 262-186-14 381-199 228+107 323-(223+65) 178+297 168+249+132+451 694+238-594.
①137+86+63,
=(137+63)+86,
=200+86,
=286;
②254+(524+146),
=524+(254+146),
=524+400,
=924;
③262-186-14,
=262-(186+14),
=262-200,
=62;
④381-199,
=381-200+1,
=182;
⑤228+107,
=228+100+7,
=335;
⑥323-(223+65),
=323-223-65,
=35;
⑦178+297,
=178+300-3,
=475;
⑧168+249+132+451,
=(168+132)+(249+451),
=300+700,
=1000;
⑨694+238-594,
=694-594+238,
=100+238,
=338.
=(137+63)+86,
=200+86,
=286;
②254+(524+146),
=524+(254+146),
=524+400,
=924;
③262-186-14,
=262-(186+14),
=262-200,
=62;
④381-199,
=381-200+1,
=182;
⑤228+107,
=228+100+7,
=335;
⑥323-(223+65),
=323-223-65,
=35;
⑦178+297,
=178+300-3,
=475;
⑧168+249+132+451,
=(168+132)+(249+451),
=300+700,
=1000;
⑨694+238-594,
=694-594+238,
=100+238,
=338.
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