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1、四年级下册交换律、结合律和分配律简便运算一、下面的算式分别运用了什么运算定律。（7分）76x18 = 18x76 (30x6x7=30x(6x7)(axb = bxa (axb ) xc = ax ( bxc )(Ax* = x 125x ( 8x40 ) = ( 125x8 ) x40 (5x4x25x2= ( 5x2 ) x(4x25 )(二、根据乘法运算定律填上合适的数。（6分）12x32 = 32x108x75 =24x5=x24( 60x25 ) x =60x ( x8 )3x4x8x5 = ( 3x4 ) x ( x35xa =x35OXQ = DXbxl25x8 = bx ( x
2、三、列竖式计算,并用乘法交换律验算。（12 分）32x18 =29x33 =69x11 =四、怎样简便就怎样算。（75分）49x40x25(25x115) x48x9x1255x4x25x2125x50x8x4125x ( 8x40 )25x7x4x316x25x12532x12525x42x468x125x84x39x254x25+16x254x25x16x2536x99(25 + 15)x4(25x15)x449x49+49x5149x99+49(68+32)x55x289x268+32x5(125x25)x4(125 + 17)x825x64x12585x82+82x1525x97+25
3、x364x15- 14x15125x8888x10287x99+8779x25+2576x101-76378+527+73167+289+3358+39+42+6136x45+36x56 3666x93+93x33+9399x3246x2536x45+36x56 3666x93+93x33+9397 + 89 + 1188x102125x8826 + 47 + 17485 + 47 + 15 + 53815+49 + 65 + 14 + 1172x12518 + 77 + 40 + 23+4871 + 73 + 69 + 74 + 68 + 70 + 69123x64 + 123x36(68+
4、32)x568+32x549x99+4936x97- 58x36+61x363000-25-4720+15/615025-25000-8-12599x23 + 2356x7 + 45x7 - 7125x13x8726x(51 + 19)900 - 178 - 122(79 + 21)-20125x72x4728x79 + 272x79(20+4)x2599x111546 (546 - 239)(20+4)x259x37+9x635x289x235x37+65x37124x25-25x2485x82+82x1532x(200+3)38x29+38(125x25)x475x299+75(4+8)x12525x(20+4)45x7+55x78x27+8x73103x328X12+8X75000-8-125165+204+335+963000-25-456x7 + 45x7 -7150-25-2
