综合套题七
189 + 523 =	9 × 7 - 17 =	6 × 9 + 79 =	864 - 6 × 6 =
(23 + 17) ÷ 8=	581 - 225 =	512 - 63 ÷ 9 =	91 - (29 + 23) =
49 ÷ 7 + 677 =	47 - 28 + 33 =	27 ÷ (31 - 22) =	58 + (85 - 48) =
68 + 26 =	1000 - 285 =	863 - 405 =	8 × (21 ÷ 7) =
556 - 218 =	49 + 42 - 62 =	(79 - 71) × 5=	85 - 56 =
408 + 294 =	85 - 37 =	508 + 6 × 4 =	639 + 346 =
27 ÷ 3 - 4 =	20 ÷ (2 × 2) =	348 + 20 ÷ 4 =	2 × (2 + 2) =
笔算下列各题（1、4小题要验算）
(1)    359 + 346 =		(2)    347 + 444 =
(3)    509 + 375 =		(4)    673 - 269 =
(5)    655 - 539 =		(6)    937 - 518 =