三年级数学简便运算 (1)284+(591+716) (2)153+178+122+547 (3)(141+229)+(371+659+1048) (4)926-348-152 (5)1584-627-373+416 (6)1276-(276+339) (7)4628-(1628-794) (8)526+498 (9)803+488 (10)938-299 (11)836-402 (12)635+327+125+(363+240) (13)9999+999+99+9+6 (14)32+34+36+38+40+42+44+46+48 (15)(1347-258)-(347+742) (16)3560-(474-440)-526 (17)12345+23451+34512+45123+51234 (18)5+10+15+20+… +95 (19)5+6+7+8+… +103+104 (20)(2+4+6+… +100)-(1+3+5+… +99) 四年级数学简便运 (1)(78+61)+39 (2)700-82-18 (3)348+163+242+410+537 (4)125×47-47×25 (5)201×316 (6)374-205+226-95 (7)3000-999 (8)997×7+21 (9)87×470+870×53 (10)(55+55+55+55×5)×125 (11)125×(8+40)×25 (12)99+49×99 (13)264×97+4×264 (14)454+999×999+545 (15)9999×36+6666×3×32 (16)124×38+65×124+76×110-76×7 (17)62×4+44×5+5×18 (18)3400-62×34-38×20-38×14 (19)1992×19911991-1991×19901990 (20(2