\(\frac{7}{35}.\frac{10}{19}+\frac{9}{19}-\frac{2}{35}\)

\(=\frac{1}{5}.\frac{10}{19}+\frac{9}{19}-\frac{2}{35}\)

\(=\frac{2}{19}+\frac{9}{19}-\frac{2}{35}\)

\(=\frac{11}{19}-\frac{2}{35}\)

\(=\frac{347}{665}\)

Bạn xem lại đề nha, vì bài trên có kết quả không được tròn lắm

~Học tốt~

\(\frac{-7}{9}.\frac{3}{11}+\frac{-7}{9}.\frac{8}{11}+\frac{17}{9}\)

\(=\frac{-7}{9}.\left(\frac{3}{11}+\frac{8}{11}\right)+\frac{17}{9}\)

\(=\frac{-7}{9}.1+\frac{17}{9}\)

\(=\frac{-7}{9}+\frac{17}{9}\)

\(=\frac{10}{9}\)

~Học tốt~

\(8\frac{2}{7}-\left(3\frac{4}{9}+\frac{42}{7}\right)\)

\(=\frac{58}{7}-\left(\frac{31}{9}+\frac{42}{7}\right)\)

\(=\frac{58}{7}-\frac{31}{9}-\frac{42}{7}\)

\(=\left(\frac{58}{7}-\frac{42}{7}\right)-\frac{31}{9}\)

\(=\frac{16}{7}-\frac{31}{9}\)

\(=-\frac{73}{63}\)

~Học tốt~

Hai vòi cùng chảy để đầy bể trong số thời gian là:

(10 + 8) : 2 = 9 (giờ)

Đáp số: 9 giờ

~Học tốt~

Hai vòi cùng chảy đầy bể trong số thời gian là :

    ( 10 + 8 ) : 2 = 9 ( giờ )

           Đáp số : 9 giờ

Câu hỏi của mẹ má mài - Toán lớp 5 - Học toán với OnlineMath Em tham khảo nhé!

Thanks bạn nhé

\(A=1+2+3+4+5+...+99+100\)

Dãy trên có số số hạng là:

(100 - 1) + 1 = 100 (số hạng)

Tổng \(A=\frac{\left(100+1\right)\cdot100}{2}=5050\)

\(B=\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{9900}\)

\(B=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{99.100}\)

\(B=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{99}-\frac{1}{100}\)

\(B=1-\frac{1}{100}\)

\(\Rightarrow B=\frac{99}{100}\)

~Học tốt~

\(\frac{1}{1.4}+\frac{1}{4.7}+\frac{1}{7.10}+...+\frac{1}{40.43}+\frac{1}{43.46}\)

\(=3.\left(1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{43}-\frac{1}{46}\right)\)

\(=3.\left(1-\frac{1}{46}\right)\)

\(=3.\frac{45}{46}\)

\(=\frac{135}{46}\)

~Học tốt~

\(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+....+\frac{3}{40.43}+\frac{3}{43.46}\)

\(=1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{40}-\frac{1}{43}+\frac{1}{43}-\frac{1}{46}\)

\(=1-\frac{1}{46}\)

\(=\frac{45}{46}\)

~ Hok tốt ~

à không, tính hoy nha

\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{2018.2019}\)

\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{2018}-\frac{1}{2019}\)

\(=1-\frac{1}{2019}\)

\(=\frac{2018}{2019}\)

~Học tốt~

x O z y t

a) Vì tia Oy nằm giữa hai tia còn lại nên:

    \(xOy+yOz=xOz\)

                  \(yOz=xOz-xOy\)

                  \(yOz=180^o-120^o\)

                  \(yOz=60^o\)

b) Vì tia Ot là phân giác của xOy nên: \(xOt=tOy=\frac{xOy}{2}=\frac{120^o}{2}=60^o\)

Vì tia Oy nằm giữa hai tia Ot và Oy nên:

\(zOy+yOt=zOt\)

\(60^o+60^o=120^o\)

\(\Rightarrow zOt=120^o\)

c) Tia Oy là tia phân giác của zOt vì:

\(zOy+yOt=zOt\)và \(zOy=yOt=60^o\)

 ~Học tốt~

1. My mother and I go to the supermarket everyday on foot.

=> My mother and I walk to the supermarket everyday.

2. How much is that coat?

=> How much does that coat cost?

3. Why don't we sing an English song?

=> What about singing an English song?

4. What's your father weight?

=> How heavy does your father weigh?

5. He spends ten minutes doing his homework.

=> It takes him ten minutes to do his homework.

~Học tốt~

Rewrite the second sentences:

1. My mother and I go to the supermarket everyday on foot.

=>_______My mother and I walk to the supermarket __________

2. How much is that coat?

=>_______What is the price of that coat / How much does that coat cost ?________

3. Why don't we sing an English song?

=>____Let's sing an English song / How about singing an English song ?_____________

4. What's your father weight?

=>_____How heavy is your father ?__________________

5. He spends ten minutes doing his homework.

=>_______It takes him ten minutes to do his homework________________