REFER

I have a lot of friends but my best friend is Anh. She is one of the classmates. We have known each other since we were 6 years old. She has a short black hair and it is straight. Her lips is small but it's very beautiful. Her eyes is very affectionately. She is tall and thin. She is very kind and and generous. She spends her free time doing volunteer work at a local orphanage but she is a hard working student who always gets good grades. Unlike me, she likes sports very much. She plays badminton very good. I am very pleased to have such a kind and understanding friend like here. I wish our friendship will last forever.

590 tự tính í nha

a,70+33-60+22-50

= 103 - 60 + 22 - 50

= 43 + 22 - 50

= 65 - 50

= 15

b, 8x(2+4+5)-79

= 8 x 11 - 79

= 88 - 79

= 9

a,70+33-60+22-50

= (70-50)+(33+22)-60

=20+55-60

=75-60

=15

b, 8x(2+4+5)-79

=8x11-79

=88-79

=9

~Study well~

#Bạch_Dương_Chi#

80-70+60-50+40-30+20=10+10+10+20=50

40,có đúng không

vì lớp 9

80-70+60-50+40-30+20
=10+10+10+20
=50

\(10+20+30+40+50+60+70+80+90+100\)

\(=\left(10+90\right)+\left(20+80\right)+\left(30+70\right)+\left(40+60\right)+\left(50+100\right)\)

\(=100+100+100+100+150\)

\(=550\)

10 + 20 + 30 + 40 + 50 +60 + 70 + 80 + 90 +100

= (10+90) + (20 + 80 ) + ( 30 + 70 ) + ( 40 + 60 )  +100 + 50

= 100 + 100 + 100 + 100 +100 + 50

= 500 + 50

= 550

\(10+20+30+40+50+60+70+80+90+100\)

\(=\left(10+90\right)+\left(20+80\right)+\left(30+70\right)+\left(40+60\right)+50+100\)

\(=10+10+10+10+50+100\)

\(=10.4+50+100\)

\(=40+50+100\)

\(=90+100\)

\(=190\)

D=\(\frac{1}{10}+\frac{4}{20}+\frac{9}{30}+\frac{25}{50}+\frac{36}{60}+\frac{49}{70}+\frac{64}{80}+\frac{81}{90}\)

=> D=\(\frac{1}{10}+\frac{2}{10}+\frac{3}{10}+\frac{4}{10}+\frac{5}{10}+\frac{6}{10}+\frac{7}{10}+\frac{8}{10}+\frac{9}{10}\)

=>  D = \(\frac{\left(1+9\right)+\left(2+8\right)+\left(3+7\right)+\left(4+6\right)+5}{10}\)

=> D =\(\frac{45}{10}=4,5\)

là 177,8 nha bạn

    \(\left(57+58+59+60+61+62+63+64+65+66+67+68+69+70\right):5\)

\(=\left[\left(70+57\right).14:2\right]:5\)

\(=\left[127.14:2\right]:5\)

\(=1778:2:5\)

\(=889:5\)

\(=\frac{889}{5}\)

177,8 nha pn