Bài: Tính
a) \(1-2-3+4+5-6-7+...+601-602-603+604\)
b) \(\frac{\left(140\frac{7}{3}-138\frac{5}{12}\right):18\frac{1}{6}}{0,002}\)
Bài: Tính
a) \(1-2-3+4+5-6-7+...+601-602-603+604\)
b) \(\frac{\left(140\frac{7}{3}-138\frac{5}{12}\right):18\frac{1}{6}}{0,002}\)
1 - 2 - 3 + 4 + 5- 6 - 7 + .... + 601 - 602 - 603 + 604
= (1 - 2 - 3 + 4) + (5 - 6 - 7 + 8) + ... + (601 -602 - 603 + 604)
= 0 + 0 + ... + 0
= 0
Tìm x, biết:
a) 60%x + 0,4x + x :3 =2
b)1-\(\left(5\frac{3}{8}+x-7\frac{5}{24}\right):\left(-16\frac{2}{3}\right)\)
c)\(3\frac{1}{4}x-\frac{7}{6}x=\frac{-5}{12}+1\frac{2}{3}\)
Bài 2: Tính:
a) A= \(\frac{-45.58-45.42}{2+4+6+...+16+18}\)
b)1-2-3+4+5-6-7+...+601-602-603+604
b) \(\frac{\left(140\frac{3}{7}-138\frac{5}{12}\right):18\frac{1}{6}}{0,002}\)
Bài 3: Cho A và B, biết:
A=\(\frac{2^{19}.27^3+15.4^9.9^4}{6^9.2^{10}+12^{10}}\) và B= \(\frac{4}{35}+\frac{4}{63}+\frac{4}{99}+\frac{4}{143}+\frac{4}{195}\)
Hãy so sánh A & B
Tính:
\(A=\frac{\left(140\frac{7}{30}-138\frac{5}{12}\right):18\frac{1}{6}}{0,002}\)
\(B=\frac{155-\frac{10}{7}-\frac{5}{11}+\frac{5}{23}}{403-\frac{26}{7}-\frac{13}{11}+\frac{13}{23}}\)
\(A=\frac{\left(140\frac{7}{30}-138\frac{5}{12}\right):18\frac{1}{6}}{0,002}\)
\(A=\frac{\left(\frac{4207}{30}-\frac{1661}{12}\right):\frac{109}{6}}{\frac{1}{500}}\)
\(A=\frac{\left(\frac{4207}{30}-\frac{1661}{12}\right)\times\frac{6}{109}}{\frac{1}{500}}\)
\(A=\left(\frac{4207}{30}-\frac{1661}{12}\right)\times\frac{6}{109}\times500\)
\(A=\frac{109}{60}\times\frac{6}{109}\times500\)
\(A=\frac{1}{10}\times500\)
\(A=50\)
\(B=\frac{155-\frac{10}{7}-\frac{5}{11}+\frac{5}{23}}{403-\frac{26}{7}-\frac{13}{11}+\frac{13}{23}}\)
\(B=\frac{5\left(31-\frac{2}{7}-\frac{1}{11}+\frac{1}{23}\right)}{13\left(31-\frac{2}{7}-\frac{1}{11}+\frac{1}{23}\right)}\)
\(B=\frac{5}{13}\)
Tính bằng cách hợp lí nhất : \(\frac{\left(140\frac{7}{3}-138\frac{5}{12}\right)\div18\frac{1}{6}}{0,002}\)
Mình nghĩ, câu này cứ tính bình thường mới là đỡ nhầm lẫn nhất đó
\(\frac{\left(140\frac{7}{3}-138\frac{5}{12}\right):18\frac{1}{6}}{0,002}=\frac{\left(\frac{427}{3}-\frac{1661}{12}\right):\frac{109}{6}}{\frac{1}{500}}=\frac{\left(\frac{1708}{12}-\frac{1661}{12}\right):\frac{109}{6}}{\frac{1}{500}}=\frac{\frac{47}{12}:\frac{109}{6}}{\frac{1}{500}}=\frac{\frac{47}{128}}{\frac{1}{500}}=\frac{5875}{32}\)
Nếu sai thì mình xin lỗi, còn nếu đúng thì bạn tick đúng cho mình nhé! cảm ơn bạn
Tính : 1-2-3+4+5-6-7+...+601-602-603+604
B=5+52+53+54+...+560
=(5+52)+(53+54)+...+(559+560)
=5(1+5)+53(1+5)+...+559(1+5)
=(5+53+...+559)(5+1)
=(5+53+...+559)6 chia hết cho 6
=>đpcm
1-2-3+4+5-6-7+...+601-602-603+604 = ?
1-2 - 3 + 4 + 5 -6 - 7 +8 +...+601 - 602 -60 3 +604
= -4 + 4 +- 8 + 8 +..........+-604+604
=0
(l ikr cho mình nhe)
\(\frac{\left(140\frac{7}{3}-138\frac{5}{12}\right):18\frac{1}{6}}{0.002}\)
\(\frac{\left(140\frac{7}{3}-138\frac{5}{12}\right):18\frac{1}{6}}{0,002}\)
\(=\frac{\left(\frac{427}{3}-\frac{1661}{12}\right):\frac{109}{6}}{0,002}\)
\(=\frac{\frac{47}{12}:\frac{109}{6}}{0,002}\)
\(=\frac{\frac{47}{218}}{0,002}\)
\(=\frac{11750}{109}\)
Ủng hộ !
Tinh: 1-2-3+4+5-6-7+...+601-602-603+604.
\(=( 1 - 2 - 3 + 4 ) + ( 5 - 6 - 7 + 8 ) + ....+ ( 601 - 602 - 603 + 604 ) = 0 + 0 + .. + 0 = 0 \)
=4+1-2-3+8+5-6-7+...+604+601-602-603
=5-(2+3)+13-(6+7)+...+1205-(602+603)
=0+0+...+0
=0
1-2-3+4+5-6-7+...+601-602-603+604
=-4+4+ -8+8 +....+ -604+604
=0+0 +...+0
=0
Bài 1: Tính:
1-2-3+4+5-6-7+...+601-602-603+604
Đặt:
\(S=1-2-3+4+5-6-7+...+601-602-603+604\)
\(S=\left(1-2-3+4\right)+\left(5-6-7+8\right)+...+\left(601-602-603+604\right)\)\(S=0+0+...+0\)
Áp dụng quy tắc: \(0.A=0\)
\(\Rightarrow S=0\)