tính nhanh (3- 1/4 +2/3) -(5-1/3-6/5) -(6-7/4+3/2)
1 2 3 4 5 6 7 8 9 = 100 đặt dấu "+" hoặc "-" để phép tính này đúng
ai giải giùm với ạ
P = 91+2+3+...+100)(1/2-1/3-1/7-1/9)(63 x 1.2 - 21 x 3.6) tất cả trên 1-2+3-4+5-6+...+99-100
A = 1*2*3+3*4*5+5*6*7+...+99*99*100
\(\dfrac{\left(13\dfrac{1}{4}-2\dfrac{5}{27}-10\dfrac{5}{6}\right).230\dfrac{1}{25}+46\dfrac{3}{4}}{\left(1\dfrac{3}{10}+\dfrac{10}{3}\right):\left(12\dfrac{1}{3}-14\dfrac{2}{7}\right)}\)
\(\dfrac{\left(1+2+3+...+99+100\right)\left(\dfrac{1}{2}-\dfrac{1}{3}-\dfrac{1}{7}-\dfrac{1}{9}\right)\left(63.1,2-21.3,6\right)}{1-2+3-4+.....+99-100}\)
A=[(3/11+1-3/7)/(3+9/11-9/7)]-[(1/3+0.25-1/5+0.125)/(7/6+7/8-0.7+7/16)]
B=1/3+1/6*(1+2)+1/9(1+2+3)+...+1/6045*(1+2+3+..+2015)
giúp vs cần gấp
a) 1+3-5-7+9+11-....-397-399
b) 1+2-3-4+5+6-....-99-100
c) 2-5+8-11+14-17+....+98-101
a) 1+3-5-7+9+11-......-397-399
b) 1+2-3-4+5+6-....-99+100
c) 2-5+8-11+14-17+....+98-101
CMR: \(\dfrac{1}{6}< \dfrac{1}{5^2}+\dfrac{1}{6^2}+\dfrac{1}{7^2}+...+\dfrac{1}{100^2}< \dfrac{1}{4}\)