Viết số thích hợp vào chỗ chấm :

4 ngày rưỡi  = .............. giờ.

Viết số thập phân thích hợp vào chỗ chấm :

336 phút = ..............giờ

Viết số thích hợp vào chỗ chấm :

0,6 giờ = .............. phút.

Viết số thích hợp vào chỗ chấm :

$\frac{3}{4}$ giờ = ............. phút.

Viết số thập phân thích hợp vào chỗ chấm :

Hai năm rưỡi = ....... năm.

Viết số thích hợp vào chỗ chấm :

Cứ ..... năm lại có 1 năm nhuận.

Viết số thích hợp vào chỗ chấm :

3 thế kỉ = .......  năm

Trong các mệnh đề sau, mệnh đề nào là mệnh đề sai?

Số tập con gồm 3 phần tử có chứa e, f của M = $\left\{ a,b,c,d,e,f,g,h,i,j \right\}$là:

Hình bên là đồ thị của ba hàm số $y={{a}^{x}}$, $y={{b}^{x}}$, $y={{c}^{x}}$$\left( 0

Tìm giá trị lớn nhất của hàm số $f(x)={{x}^{2}}{{e}^{x}}$ trên đoạn $\left[ -1;1 \right]$?

For more than six million American children, coming home after school means coming back to an empty house. Some deal with the situation by watching TV. Some may hide. But all of them have something in common. They spend part of each day alone. They are called “latchkey children”. They are children who look after themselves while their parents work. And their bad condition has become a subject of concern. Lynette Long was once the principal of an elementary school. She said, “We had a school rule against wearing jewelry. A lot of kids had chains around their necks with keys attached. I was constantly telling them to put the keys inside shirts. There were so many keys; it never came to my mind what they meant.” Slowly, she learned that they were house keys. She and her husband began talking to the children who had keys. They learned of the effect working couples and single parents were having on their children. Fear was the biggest problem faced by children at home alone. One in three latchkey children the Longs talked to reported being frightened. Many had nightmares and were worried about their own safety. The most common way latchkey children deal with their fears is by hiding. They may hide in a shower stall, under a bed or in a closet. The second is TV. They often turn the volume up. It’s hard to get statistics on latchkey children, the Longs have learned. Most parents are slow to admit that they leave their children alone

The phrase “an empty house” in the passage mostly means ______.

One thing that the children in the passage share is that ______.

The phrase “latchkey children” in the passage means children who ______.

The main problem of latchkey children is that they ______.

What is the main idea of the first paragraph?

Why did a lot of kids have chains around their necks with keys attached?

What do latchkey children suffer most from when they are at home alone?

Lynette Long learned of latchkey children’s problems by ______.

What is the most common way for latchkey children to deal with fears?

What might be the purpose of this passage?

Tìm tập hợp tất cả các giá trị của tham số thực m để hàm số $y=\ln \left( {{x}^{2}}+1 \right)-mx\text{+1}$ đồng biến trên khoảng $\left( -\infty ;+\infty  \right)$.

The habits of those who constantly play video games are very important to people working in videogame industry. If video games are going to be one of the most attractive features of future interactive systems, it is essential for producers to know what types of games to make, how best to present such games on interactive video and how to ensure that such games maintain their fascination for people. Above all, it is vital to build up detailed profiles of people who are addicted to video games. Until recently, the chief market for video games has been boys aged eight to fifteen. The fascination for interactive video games is seen in its purest form in this group. Video games appeal to some deep instinct in boys who find it impossible to tear themselves away from them. Schoolwork is ignored, health is damaged and even eating habits are affected. Girls of the same age, however, are entirely different, demonstrating far greater freedom from the hold of video games. Quite simply, they can take video games in their stride, being able to play them when they want and then leave them alone.

Producers of video games are keen on _____ .

The people who are most attracted to video games are______.

Tập các giá trị thực của tham số m để hàm số $y={{x}^{3}}-\left( m+1 \right){{x}^{2}}-\left( 2{{m}^{2}}-3m+2 \right)x+2{{m}^{2}}-m$ đồng biến trên nửa khoảng $\left[ 2;+\infty  \right)$ có dạng $\left[ a;b \right]$. Tính $a+b$