小升初运算1

(2) (2. 3+2. 3+2. 3+2. 3) X2.5,\r21 =2. 3X4X2. 5,\r=8. =2. 3 X (4X2.5),\r3 =2.3X10,\r(4) 21X ( l ^ ) , =23\r55. (1) ( _ L - 1 )\r= 2 1 X _ l / x 2 1 , 9 16 4 2\r7 1.\r=^X-AX 2,\r9 16\r=1.\r3\r(2) 78-r[32X ( 1 - 5 ) +144]\r8\r=78+[32X2+144],\r8\r=784-[12+144],\r=784-156,\r=0.5"\r(3) _L x J - -2.X J\r15 5 15 5\r= (L 2 ) x 4\r15 15 5\r_ l x 4\r3 5\r= 4 .\r15