Angle : If two line segments (or rays) both start at a common point the opening between the two line segments is called an angle. The common point is called vertex of the angle. The size of an angle is measured in degrees.

Corner : A corner of a shape is a point in the shape such that this point does not lie on the line segment between any two other points in the shape. Every triangle has 3 corners and every quadrilateral has 4 corners.

Number : A number $x$ is a mathematical symbol representing a quantity.

Square : A square is a quadrilateral with four right angles and four equal length sides. A square is a special case of a rectangle and a special case of a rhombus.

Same as the number of corners.

The correct answer is 4. A square has 4 angles.

Number : A number $x$ is a mathematical symbol representing a quantity.

Find a number that multiplied with 4 equals 40.

The correct answer is 10. $40\div4=10.$

Favorable outcome : In a random experiment the favorable outcomes are the outcomes of the event of which we want to calculate the probability. For example if we want to calculate the probability of throwing an even number with a dice the favorable outcomes are 2, 4 and 6.

Half : A Half is the number equal to $\frac{1}{2}=0.5.$

Number : A number $x$ is a mathematical symbol representing a quantity.

Possible outcome : Any outcome of a random experiment.

Probability : A probability is a number between 0 and 1 that describes how likely an outcome is. For discrete events that are equally likely the probability can be calculated by dividing the number of favorable outcomes by the number of possible outcomes.

Reduced fraction : A reduced fraction (or simplified fraction or fraction in simplified form or fraction in simplest form) is a fraction $\frac{a}{b}$ such that $a$ and $b$ do not have any common factors bigger than 1. For example the reduced fraction of the fraction $\frac{4}{6}$ is $\frac{2}{3}.$

The first throw does not matter for the second throw.

The correct answer is 1/2. There are two possible outcomes for the second throw: heads and tails. There is one favorable outcome: heads. Dividing the number of favorable outcomes by the number of possible outcomes we get a probability of $\frac{1}{2}.$