=20 dễ ợt

132:25+368:25

= ( 132 + 368 ) : 25

= 500 : 25

= 20

#HOK TỐT #

132 : 25 + 368 : 25 

=( 132 + 368 ) : 25 

= 500 : 25

=20

Học tốt !

X:12=132(dư 7)

X=132x12+17

x=1591

Vậy x=1591

2897:X=25(dư 4)

25xX+4=2879

25xX=2879-4

25xX=2875

X=2875:25

X=115

Vậy X=115

368:X=24(dư 8)

24xX+8=368

24xX=368-8

24xX=360

X=360:24

X=15

Vậy X=15

Tôi biết là mình làm sai nhưng bạn kia làm sai đâu,sao ai k sai cho bạn ấy?

\(\frac{25}{72}+\frac{25}{90}+\frac{25}{110}+...+\frac{25}{9900}\)

= \(25.\left(\frac{1}{72}+\frac{1}{90}+\frac{1}{110}+...+\frac{1}{9900}\right)\)

= \(25.\left(\frac{1}{8.9}+\frac{1}{9.10}+\frac{1}{10.11}+...+\frac{1}{99.100}\right)\)

= \(25.\left(\frac{1}{8}-\frac{1}{9}+\frac{1}{9}-\frac{1}{10}+\frac{1}{10}-\frac{1}{11}+...+\frac{1}{99}-\frac{1}{100}\right)\)

= \(25.\left(\frac{1}{8}-\frac{1}{100}\right)\)

= \(25.\frac{23}{200}\)

= \(\frac{23}{8}\)

\(13^2+\left(25x-4^2\right):17=171\)

\(\Leftrightarrow\left(25x-4^2\right):17=171-169\)

\(\Leftrightarrow\left(25x-4^2\right):17=2\)

\(\Leftrightarrow25x-16=34\Leftrightarrow25x=50\Leftrightarrow x=2\)

1 2 2 + 1 3 2 + 1 4 2 + ... + 1 9 2 > 1 2.3 + 1 3.4 + 1 4.5 + ... + 1 9.10 = 2 5

1 2 2 + 1 3 2 + 1 4 2 + ... + 1 9 2 < 1 1.2 + 1 2.3 + 1 3.4 + 1 8.9 = 8 9

nhanh đi

99-97+95-93+91-89+...+7-5+3-1

Số các số hạng là:

(99-1):2+1=50 số

=(99-97)+(95-93)+(91-89)+...+(7-5)+(3-1)

Số cặp sẽ là:

50:2=25 cặp

=2+2+2+...+2+2

=2x25

=50

32x47+32-53+168+79+132

=1504+32-53+(168+79+132)

=1536-53+379

=1483+379

=1862

25/2+25/3-25/7/1/3+1/3-1/7

\(=\frac{25}{2}+\frac{25}{3}-\frac{25}{7}:\frac{1}{3}+\frac{1}{3}-\frac{1}{7}\)

\(=\frac{25}{2}+\frac{25}{3}-\frac{25}{7}\times\frac{3}{1}+\frac{1}{3}-\frac{1}{7}\)

\(=\frac{25}{2}+\frac{25}{3}-\frac{156}{7}+\frac{1}{3}-\frac{1}{7}\)

\(=\frac{525}{42}+\frac{350}{42}-\frac{936}{42}+\frac{14}{42}-\frac{6}{42}\)

\(=\frac{875}{42}-\frac{936}{42}+\frac{14}{42}-\frac{6}{42}\)

\(=\frac{-61}{42}+\frac{14}{42}-\frac{6}{42}\)

\(=\frac{-47}{42}-\frac{6}{42}\)

\(=\frac{-53}{42}\)

( Chú Ý: lớp 5 chưa học số âm )

a