70-(12+8)计算时先算什么法再算什么法结果是什么

昌度齿32162+4+6+8+10+12+12+16......+56 简便计算 -
容卓桑17728439298 ______ 2+4+6+8+10+12+12+16......+56 公差为2 项数为 (56-2)/2 +1 = 27+1 = 28 和= (2+56) x 28 /2 = 58 x 14 =812

昌度齿32160.7x12/8怎么算 -
容卓桑17728439298 ______ 解:du0.7*12/8等于( 21/10 ),【即等zhi于dao1.05】 ∵已内知需求出0.7*容12/8等于多少 A * B = A * B = C ∴0.7 * 12/8 = 7/10 * 3/2 = 21/10 = 1.05 答:0.7*12/8等于21/10,【即等于1.05】

昌度齿32161.用“代数和”计算,1.计算.( - 7) - ( - 8)+( - 9) - 14 ( - 32) - 17 - ( - 65)+5 ( - 7.7)+( - 2.3) - 5.6 - ( - 12.6)( - 1/2) - ( - 1/3)+( - 1/4) -
容卓桑17728439298 ______[答案] (-7)-(-8)+(-9)-14 =-7+8-9-14 =1-9-14 =-8-14 =-22 (-32)-17-(-65)+5 =-32-17+65+5 =-49+70 =21 (-7.7)+(-2.3)-5.6-(-12.6) =-7.7-2.3-5.6+12.6 =-10+7 =-3 (-1/2)-(-1/3)+(-1/4) =-1/2+1/3-1/4 =-6/12+4/12-3/12 =-2/12-3/12 =-5/12

昌度齿3216计算:( - 8又1/3) - (+12) - ( - 70又1/2) - ( - 8又1/3) -
容卓桑17728439298 ______ :(-8又1/3)-(+12)-(-70又1/2)-(-8又1/3) =-25/3-12+151/2+25/3 =-24/2+151/2 =127/2

昌度齿3216( - 12)+11+( - 8)+( - 7)+39+7用两种方法计算 -
容卓桑17728439298 ______ =-12+11-8-7+39+7=30 =(-12-8-7)+11+39+7=-27+57=30

昌度齿32161.2乘6.8乘8用简便方法计算 -
容卓桑17728439298 ______ 1.2*6.8*8 =1.2*8*6.8 =9.6*6.8 =(10-0.4)*(7-0.2) =70 - 2 - 2.8 + 0.08 =70.08 - 4.8 =65.28

昌度齿321612+( - 13)+8+( - 7) 计算 -
容卓桑17728439298 ______ 12+(-13)+8+(-7)=12+8-(13+7)=20-20=0

昌度齿3216因为7*8=56,所以70*8= - -----;计算14*3时,先算------*3=------,再算------*3=------,最后算---- -
容卓桑17728439298 ______ 因为7*8=56,所以70*8=560;计算14*3时,先算10*3=30,再算4*3=12,最后算30+12=42. 故答案为:560,10,30,4,12,30+12=42.

昌度齿3216(12+8)*56用(脱式简便方法计算) -
容卓桑17728439298 ______ (12+8)*56=20*56=20*(50+6)=1000+120=1120

昌度齿3216计算3/4 - 9/28+12/70 - 18/130+21/208的值 -
容卓桑17728439298 ______[答案] 3/4-9/28+12/70-18/130+21/208 =21/28-9/28+12/70-18/130+21/208 =3/7+12/70-18/130+21/208 =30/70 +12/70-18/130+21/208 =6/10-18/130+21/208 =78/130-18/130+21/208 =6/13 + 21/208 =96/208 + 21/208 =117/208 =9/16