Tổng số phần Lan đã đọc là: \(\frac{2}{9}\) + \(\frac{7}{18}\) = \(\frac{11}{18}\) (quyển sách)

Số phần Lan còn phải đọc thì hết quyển sách là: 1- \(\frac{11}{18}\) = \(\frac{7}{18}\) (quyển sách)

Vậy Lan còn phải đọc \(\frac{7}{18}\) thì hết quyển sách.

[195+937] x 9

=1132 x 9

=10188
 

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

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

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

Ta lại có : 3M = 3 -1 +\(\frac{1}{3}-\frac{1}{3^2}+\frac{1}{3^3}-......+\frac{1}{3^{97}}-\frac{1}{3^{98}}\)

M + 3M = 3 - \(\frac{1}{3^{99}}\)

4M = 3 - 1/3⁹⁹ => M = 3/4 - 1/4.3⁹⁹

Khi đó : 4A = ( 3/4 - 1/4.3⁹⁹) - 1/3⁹⁹

4A = 3/4 - 1/4.3⁹⁹ - 1/3⁹⁹ < 3/4

=> A < 3/4 : 4

=> A < 3/16 (đpcm)

St.Valentine’s Day is a celebration for romance and love. This holiday comes from an ancient Roman festival called the Feast of Lupercalia after a Roman called St.Valentine who was martyred for refusing to give up Christianity. He died on February 14th, and the date was set aside to honor him. St.Valentine was named a patron saint of love and February 14th became the date of exchanging love letters or messages and for sending flowers ( usually red rose) and chocolate candy to a loved one. St.Valentine’s Day colors are red and white. School children have classroom party with Valentine candy and pass out Valentine cards to each other.

1. Is St. Valentine’s Day a celebration of romance and love?

Yes, it is

2. Where does this holiday come from?

An ancient Roman festival called the Feast of Lupercalia

3. Whey is St. valentine’s Day celebrated on February 14th?

Because the date was set aside to honor St.Valentine

4. What do people do on this day?

Exchanging love letters or messages and for sending flowers ( usually red rose) and chocolate candy to a loved one

5. List the two colors of St. valentine’s Day?

Red and white

6. How do school children hold St. Valentine’s Day?

School children have classroom party with Valentine candy and pass out Valentine cards to each other.

50.49:2= tự tính

chưa chắc đã đúng!!!!!!!

\(1\frac{5}{7}\)x \(\frac{3}{4}\)

= \(\frac{12}{7}\)x \(\frac{3}{4}\)

= \(\frac{36}{28}=\frac{9}{7}\)

đ/s:\(\frac{9}{7}\)