# Math
## The Math Blocks
There are thirteen kinds of *math* blocks you can use in the Dynamic Engine. This article focuses on the six most common blocks you will use:
1. Specific Number
2. Random Number
3. Random Fraction
4. Basic Equation
5. Sum of List
6. Round
### Math: Specific Number
The **specific** **number** block lets you specify a specific number. For example, the following specific number block is set to "100".
### Math: Random Number
The **random number** block randomly generates a number between two numbers with specified increments. For example, the following random number block sets the block to a random number from "0" to "100", in steps of "10".
For further clarity, the above example would create a random number that could be 0, 10, 20... up to 100.
### Math: Basic Equation
The **basic equation** block lets you specify mathematical operations with specific numbers or variables. For example, the following blocks first set the variable "number" to a random number between "0" and "100", in increments of "10", and then using a **basic equation** block adds the number "1" to the variable "number" to a new variable called "new number".
There are five mathematical operators within the dropdown menu of the **basic equation** block:
* **x** multiplied by
* **รท** divided by
* **+** add to
* **-** subtract from
* **^** to the power of
You can nest multiple basic equation blocks inside of each other, creating a whole world of possibilities. For example, the following two basic equation blocks were combined to (1) double the variable "number" and (2) take it to the power of "3".
### Math: Sum of List
The **sum of list** block adds all the values in a list. It must be combined with a **list** block in order to work. For example, the following blocks set the variable "number" to 10, by adding the **specific number** blocks "2", "3", and "5" together.
There are eight operators within the dropdown menu of this block:
* **sum:** add all values in a list together
* **min:** finds and returns the minimum value in a list
* **max:** finds and returns the maximum value in a list
* **average:** calculates the simple average value of a list
* **median:** finds and returns the median value in a list
* **modes:** finds and returns the mode(s) in a list
* **standard deviation:** calculates the standard deviation of a list
* **random item:** finds and returns a random value from a list
### Math: Round
The **round** block rounds a value to the nearest whole number. For example, the following blocks set the variable "number" to the value "3", by rounding 3.14159 down to 3.
There are three operators within the dropdown menu of this block:
* **round:** rounds to the nearest whole number
* **round up:** rounds up to the nearest whole number
* **round down:** rounds down to the nearest whole number
{% hint style="info" %}
If you want to round to a specific number of decimal places, you'll need to multiply by 10, round, then divide by 10.
{% endhint %}
***
## Example Question
Consider the following multiple-choice question.
The goal of this question is to change the data for each student.\
\
Here is what the Dynamic Engine would look like:
What's happening here is that the Dynamic Engine is generating 3 random numbers within specified limits, it then creates three answer options, two of which are functional distractors with those random numbers.\
\
Here is what the sample question would look like (values highlighted in blue for convenience):
{% hint style="info" %}
The Dynamic Engine will never allow two choices to be identical for answer choices in an assessment.
{% endhint %}
