= 5

nhớ tk nka

29843

cho mjk nhe 

jhjhj

457 * 23 + 222 * 89 - 426 = 29843

a) 12 + 23 + 34 + 45 + 56 + 67 + 78 + 89

= ( 12 + 78 ) + ( 23 + 67 ) + ( 34 + 56 ) + ( 45 + 89 )

= 90 + 90 + 90 + 132

= 90 x 3 + 132

= 270 + 132

= 402

b) 125 x 6 x 7 x 8

= 750 x 7 x 8

= 5250 x 8

= 42000

c) ( 56 x 78 + 56 x 47 ) : 7 

= 56 x ( 78 + 47 ) : 7

= 56 x 125 : 7

= 7000 : 7

= 1000

a) 12 + 23 + 34 + 45 + 56 + 67 + 78 + 89

= ( 12 + 78 ) + ( 23 + 67 ) + ( 34 + 56 ) + ( 45 + 89 )

= 90 + 90 + 90 + 132

= 90 x 3 + 132

= 270 + 132

= 402

b) 125 x 6 x 7 x 8

= 750 x 7 x 8

= 5250 x 8

= 42000

c) ( 56 x 78 + 56 x 47 ) : 7 

= 56 x ( 78 + 47 ) : 7

= 56 x 125 : 7

= 7000 : 7

= 1000

a) 89 + 10 x 2 = 89 + 20

                   = 109

b) 25 x 2 + 78 = 50 + 78

                   = 128

c) 46 + 77 x 2 = 46 + 14

                   = 60

d) 35 x 2 + 90 = 70 + 90

                   = 160

(23 + 24 + 25 + ...+ 57) x 0

=0

a ) 3 5 : 1 2 . 3 5 = 3 5 : 3 10 = 3 5 . 10 3 = 2

b ) 4 5 + 3 5 : 3 − 7 8 = 4 5 + 1 5 − 7 8 = 1 − 7 8 = 1 8 c ) 3 4 : 2 3 : 3 5 = 1 8 : 3 5 = 1 8 . 5 3 = 15 8 d ) 5 12 . 21 15 : 1 4 = 7 12 .4 = 7 3

12 + 23 + 23 + 56 + 78 + 89 + 0,1 + 0,89, 88,99

= 370,98

ủng hộ 

mk nha pạn!

h​u hu giúp với huhu

\(A=1-1-\dfrac{5}{6}+1+\dfrac{7}{12}-1-\dfrac{9}{20}+1+\dfrac{11}{30}-1-\dfrac{13}{42}+1+\dfrac{15}{56}-1-\dfrac{17}{72}+1+\dfrac{19}{90}\)

\(=1-\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}+\dfrac{1}{4}-\dfrac{1}{4}-\dfrac{1}{5}+...+\dfrac{1}{9}+\dfrac{1}{10}\)

=1/2+1/10

=5/10+1/10=6/10=3/5

a = (81+19)+35

=100+35=135

b = (78+22)+(65+135)

=100+200=300

c = (234+17716)+23

=17950+23=17973

d = (99+1)+85

=100+85=185

a) 81 + 35 + 19 = (81 + 19) + 35 = 100 + 35 = 135

b) 78 + 65 + 135 + 22 = (78 + 22) + (135 + 65) = 100 + 200 = 300

c) 234 + 17716 + 23 = 17950 + 23 = 17973

d) 85 + 99 + 1 = 85+ (99 + 1) = 85 + 100 = 185