Algebra
x/2 + 8 = -13
x = -42
A knight wants to save a princess in a tower. The tower has a lock with a code consisting of 6 digits. What is the maximum number of codes the knight has to enter to save the princess?
106 = 1000000
-1(1)2-1+1+1-1-(-1)
0
A cube's volume is 27cm3. Find the surface area.
SA = 56cm2
There are six glasses alternating between full and empty: full, empty, full, empty, full, empty.
You can only touch one glass. How to arrange the glasses in this pattern: full, full, full, empty, empty, empty?
Pour water from the fifth glass to the second one.
What is the degree of this polynomial: 2x2xy3 - 0.8x2y2c3
7
There are five paths leading to the top of a mountain. An explorer climbs up one path and goes down a different path. How many ways can the explorer go up and down the mountain?
20
((122*1-2)(395/79))
740
A rhombus' inner acute angle is 40 degrees. What is its inner obtuse angle?
140 degrees
Two fathers and two sons ate an egg for breakfast. There were three eggs, but each ate a whole egg. How?
There was a grandfather, a father, and a son.
Factorize: a3x - a2x
a2x (ax - 1)
A girl went into a cafe. There were four kinds of milkshakes, ten kinds of ice cream, and three types of cones. The girl has enough money only for either one type of milkshake or one type of ice cream together with one type of cone. How many types of treats can the girl get?
34
ME + M = ASA
92 + 9 = 101
A plumber has a roll of duct tape with five layers left on it. The diameter of the roll is 10 cm. He wants to tape a pipe with the remaining duct tape. What is the largest pipe radius to cover the pipe with one layer of tape?
25 cm
A man on the market was selling a parrot. He said to a customer "This parrot repeats every word he hears!" The customer bought the parrot and talked with him for several days. The parrot didn't say anything. Why?
The parrot was deaf.
Factorize: x2 - 2x - xy + 2y
(x - 2)(x - y)
I have three bags, one with blue balls, one with green balls, and the other with yellow balls. How many possible combinations are there if I take out four random balls and put them in order?
81
Calculate which part is larger without a calculator:
(452 - 312) or (442 - 302)
(45+31)(45-31) or (44+30)(44-30)
76*14 or 74*14
76 > 74
A triangular prism's base is an equilateral triangle. The perimeter of its rectangular side is 38 cm. Calculate the area of the base if the prism's height is 11 cm.
Sixteen times square root of three cm2
One day, a boy met a man walking on the street. "How old are you?" asked the boy. "If you multiply my age by 18, you will get 1421." The boy immediately knew the man was lying. How?
If you multiply a number by 18, you will get an even number. 1421 is an odd number.
Simplify:
(12 - y) / (6y - 36) + 6 / (6y - y2)
(6 - y) / 6y
On a faraway planet, the aliens' alphabet consists of four letters : A, B, C, and D. The names of the aliens consist of three letters, but cannot include the letter D. How many possible names are there?
27
How many integers are in the interval (non-inclusive) between the square root of 8 and the square root of 81?
6
A cube is placed inside a sphere such that all its vertices are touching the surface of the sphere. The volume of the cube is 2/π√3 m3. Find the volume of the sphere.
1 m3
Three logicians walk into the bar. They are asked "Is everyone drinking?" The first and second say "I don't know" but the third says "Yes". Why?
The first is drinking, but he doesn't know if the others are, so he says "I don't know". The second is also drinking, but he doesn't know that the third is, so he says "I don't know". The third is drinking, so he says yes.