a)\(\frac{25.4-0,5\cdot40\cdot0,2\cdot20\cdot0,25}{1+2+8+...+129+156}\)
\(=\frac{100-100}{1+2+8+...+156}\)
\(=\frac{0}{1+2+8+...+156}\)
\(=0\)
b)\(\frac{0,5\cdot40-0,5\cdot20\cdot8\cdot0,1\cdot0,25\cdot10}{128:8.16.4\left(4+52:4\right)}=\frac{20-20}{128:8.16.4.\left(4+52:4\right)}=\frac{0}{128:8.16.4.\left(4+52:4\right)}=0\)
Tính nhanh
A = \(\frac{120-0,5\cdot40,5\cdot0,2\cdot20\cdot0,25-20}{1+5+9+...+33+37}\)
NHANH LÊN NHA MK ĐANG GẤP
tính nhanh
e) \(\frac{0,1997+2,5\cdot12,5\cdot0,4\cdot0,08+0,8003}{1,25\cdot2,5\cdot8\cdot4}\)
g)\(\frac{\left(10,6524+0,3476\right)\cdot125\cdot0,4+8}{4\cdot0,1\cdot8\cdot0,25\cdot125}\)
tính nhanh
\(\frac{0,8\cdot0,4\cdot1,25\cdot25+0,725+0,275}{1,25\cdot4\cdot8\cdot25}\) \(\frac{9,6\cdot0,2\cdot15,4\cdot2\cdot15,4:0,25}{30,8:0,5\cdot40:0,125\cdot5\cdot6}\)
so sánh A và B biết
A=\(\frac{1\cdot2+2\cdot4+3\cdot6+4\cdot8+5\cdot10}{3\cdot4+6\cdot8+9\cdot12+12\cdot16+15\cdot20}\)
B=\(\frac{111111}{666665}\)
tính nhanh]
b)\(\frac{1\cdot10+2\cdot19+3\cdot18+4\cdot17+.....+18\cdot3+19\cdot2+20\cdot1}{20\cdot\left(1+2+3+.....+19+20\right)-\left(1\cdot2+2+3+3\cdot4+.....+19\cdot20\right)}\)
A=\(A=\frac{1\cdot3\cdot5+2\cdot6\cdot10+4\cdot12\cdot20+7\cdot25\cdot35}{1\cdot5\cdot7+2\cdot10\cdot19+4\cdot20\cdot28+7\cdot35\cdot49}\)
* là dấu nhân
A = \(\frac{1\cdot2+2\cdot4+3\cdot6+4\cdot8+5\cdot10}{3\cdot4+6,8+9\cdot12+12\cdot6+15\cdot20}\)
B = \(\frac{111111}{666665}\)
so sánh 2 số
1) Tính
a)\(\frac{13}{15}+\frac{13}{35}+\frac{13}{63}+\frac{13}{99}\)
b)\(\left(\frac{15}{1\cdot2\cdot3}+\frac{15}{2\cdot3\cdot4}+\frac{15}{3\cdot4\cdot5}+.....+\frac{15}{18\cdot19\cdot20}\right)\cdot x=1\)
so sánh\(\frac{1\cdot3\cdot5+2\cdot6+4\cdot12\cdot20+7\cdot21\cdot35}{1\cdot5\cdot7+2\cdot10\cdot14+4\cdot20\cdot28+7\cdot35\cdot49}\)với \(\frac{303}{708}\)
