计算:2/(1*3)+2/(3*5)+2/(5*7+2/(7*9)+...+2/(95*97)+2/(97*99)=?
先观察,后计算(1)计算自然数1,2,3,.,999的和(2)计算1+3+5+...+297+299(3)计算100-9
1-2+3+4-5+6+7-8+9+10-11+12+...97-98+99怎么计算规律计算
计算1+3+5+7…+(2n+1)
计算:2/(1*3)+2/(3*5)+2/(5*7+2/(7*9)+...+2/(95*97)+2/(97*99)=?
简便计算:(20+2)×7×5
能简便计算的简便计算:【1-(1-2/3/2/3)】*7/18
计算(2+4+6+.+96+98+100)-(1+3+5+.+95+97+99)
(5/24+7/12-2/3)*48简便计算
简便计算5/6-(3/4-1/2)=
计算解题({【2】})
计算:(-5a^6)²+(-3a³)³.a³ 计算:(x-2)(x+7)-2(3
"2计算"和"3计算",