1.2.3.4...9=362880

1 . 2 . 3 . 4 . 5 . 6 . 7 . 8 . 9

362880

\(\frac{1}{1}+2+\frac{1}{1}+2+3+\frac{1}{1}+2+3+4+\frac{1}{1}+2+3+4+5\)

\(=1+2+1+2+3+1+2+3+4+1+2+3+4+5\)

\(=\left(1\times4\right)+\left(2\times4\right)+\left(3\times3\right)+\left(4\times2\right)+5\)

\(=4+8+9+8+5\)

\(=4+5+9+8\times2\)

\(=4+5+9+16\)

\(=\left(4+16\right)+14\)

\(=20+14=34\)

k cho tớ nha bn

\(\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}+\frac{1}{1+2+3+4+5}\)

\(=\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+\frac{1}{15}\)

\(=\frac{2}{3}\)

Đáp số : 34
 

(dấu . là dấu nhân )

a, \(\frac{3}{2}\cdot\frac{4}{7}+\frac{3}{7}\cdot\frac{3}{2}\)

= \(\frac{3}{2}\left(\frac{4}{7}+\frac{3}{7}\right)\)

=\(\frac{3}{2}\cdot\frac{7}{7}=\frac{3}{2}\)

b, \(\frac{12}{5}\cdot4-4\cdot\frac{7}{5}\)

=\(4\left(\frac{12}{5}-\frac{7}{5}\right)=4\cdot\frac{5}{5}=4\)

c, \(\frac{5}{11}:\frac{1}{2}+\frac{6}{11}:\frac{1}{2}\)

=\(2\left(\frac{5}{11}+\frac{6}{11}\right)=2\cdot\frac{11}{11}=2\)

a;3/2x(4/7+3/7)

=3/2x1

=3/2

b;12/5x4-4x7/5

=4x(12/5-7/5)

=4x1

=4

c;5/11:1/2+6/11:1/2

=1/2:(5/11+6/11)

=1/2:1

=1/2

a) 3/2 * 4/7 +3/7 * 3/2

= 3/2*(4/7+3/7)

= 3/2*1

=3/2

b) 12/5 * 4 -4*7/5

=4*(12/5-7/5)

= 4*1

=4

c) 5/11 :1/2 + 6/11 : 1/2

=1/2 : (5/11 +6/11)

=1/2 : 1

=1/2

\(6+7=13\)

\(2+3=5\)

\(5+7=12\)

\(99-73=26\)

\(2324234-344=2323900\)

\(65\div5=13\)

6 + 7 = 13

2 + 3 = 5

5 + 7 = 12

99 - 73 = 26

2324234 - 344 = 2323890

65 : 5 = 13

đáp án lần lượt là :13,5,12,26,2323890,13 minh nhanh

ko có bạn nào biết làm hả ?????? làm ơn 

so ez!!!đáp án =0

Mời kết bạn đi!ahihi 🐈

but how

bằng 4  nha

2 + 2 = 4

Đáp số: 4

có như vậy cũng ko biết

a)  \(\frac{3}{4}\times\frac{1}{2}\times2\)

C1: \(=\frac{3}{8}\times2=\frac{3}{4}\)

C2:  \(=\frac{3}{4}\times1=\frac{3}{4}\)

b)  \(\left[\frac{3}{4}+\frac{1}{2}\right]\times\frac{5}{7}\)

C1:  \(=\frac{5}{4}\times\frac{5}{7}=\frac{25}{28}\)

C2:   \(=\frac{3}{4}\times\frac{5}{7}+\frac{1}{2}\times\frac{5}{7}=\frac{15}{28}+\frac{5}{14}=\frac{25}{28}\)

a/\(\frac{3}{4}\cdot\frac{1}{2}\cdot2=\frac{6}{8}\cdot2=\frac{12}{8}=\frac{3}{2}\)

\(\frac{3}{4}\cdot\frac{1}{2}\cdot2=\frac{3}{4}\cdot\frac{2}{2}=\frac{3}{4}\cdot1=\frac{3}{4}\)

b/\(\left(\frac{3}{4}+\frac{1}{2}\right)\cdot\frac{5}{7}=\frac{5}{4}\cdot\frac{5}{7}=\frac{25}{28}\)

\(\left(\frac{3}{4}+\frac{1}{2}\right)\cdot\frac{5}{7}=\frac{3}{4}\cdot\frac{5}{7}+\frac{1}{2}\cdot\frac{5}{7}=\frac{15}{28}+\frac{5}{14}=\frac{15}{28}+\frac{10}{28}=\frac{25}{28}\)

c/\(\frac{5}{7}\cdot\frac{13}{21}+\frac{2}{7}\cdot\frac{13}{21}=\frac{65}{147}+\frac{26}{147}=\frac{91}{147}=\frac{13}{21}\)

\(\frac{5}{7}\cdot\frac{13}{21}+\frac{2}{7}\cdot\frac{13}{21}=\left(\frac{5}{7}+\frac{2}{7}\right)\cdot\frac{13}{21}=1\cdot\frac{13}{21}=\frac{13}{21}\)

Học tốt @#_#@

<br class="Apple-interchange-newline"><div id="inner-editor"></div>34 ·12 ·2=68 ·2=128 =32 

34 ·12 ·2=34 ·22 =34 ·1=34 

b/(34 +12 )·57 =54 ·57 =2528 

(34 +12 )·57 =34 ·57 +12 ·57 =1528 +514 =1528 +1028 =2528 

c/57 ·1321 +27 ·1321 =65147 +26147 =91147 =1321 

57 ·1321 +27 ·1321 =(57 +27 )·1321 =1·1321 =1321 

Học tốt @#_#@

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Phạm Trà My

<br class="Apple-interchange-newline"><div id="inner-editor"></div>34 ·12 ·2=68 ·2=128 =32 

34 ·12 ·2=34 ·22 =34 ·1=34 

b/(34 +12 )·57 =54 ·57 =2528 

(34 +12 )·57 =34 ·57 +12 ·57 =1528 +514 =1528 +1028 =2528 

c/57 ·1321 +27 ·1321 =65147 +26147 =91147 =1321 

57 ·1321 +27 ·1321 =(57 +27 )·1321 =1·1321 =1321 

a, b: ở trên.

c. (x+1)+(x+3)+...+(x+97)+(x+99)=0 (có 50 cặp) 

=> x+1+x+3+...+x+97+x+99 = 0

=> (x+x+...+x)+(1+3+...+97+99)=0

=> 50x+\(\frac{\left(99+1\right).50}{2}\)=0

=> 50x+2500=0

=> 50x=-2500

=> x=-2500:50

=> x=-50