# Problem Set: Math

This section contains a number of selected problems for the Math section.

It is recommended that you review the problems, and complete a few before moving on to the next section.

## Problem #1: Apples to Oranges

Use variables in JavaScript to store the number of fruit each person has.

1. Randy has 5 apples
2. Chris has 12 lemons
3. Anna has 3 more apples than Randy
4. Janet has 2 less lemons than Chris
5. Tom has a number of oranges equal to the number of lemons Janet has minus the number of apples Anna has

## Problem #2: Difficult Math

Math can be hard, but computers are good at it. Use JavaScript to compute the following:

Equation Equation
(a) `15,391` + `4,273` = (g) `87,849,383` ÷ `7,481` =
(b) `12,589` + `2,531` = (h) `72,395,941` ÷ `16,063` =
(c) `13,577` - `8,039` = (i) `9,439` - `4,831` + `8,237` =
(d) `3,307` - `1,103` = (j) `4,567` - `3,761` × `2,281` =
(e) `10,177` × `13,159` =    (k) `3,337` × `8,633` ÷ `4,183` =
(f) `3,089` × `4,111` = (l) `10,181` + `112,911,179` ÷ `12,049` =

## Problem #3: Apples to Oranges II

Use variables in JavaScript to store the number of fruit each person has.

1. Randy has `||variables:x||` apples
2. Chris has `||variables:y||` lemons
3. Anna has 3 more apples than Randy
4. Janet has 2 less lemons than Chris
5. Tom has a number of oranges equal to the number of lemons Janet has minus the number of apples Anna has

This equation for different values of `||variables:x||` and `||variables:y||`. Start with `x = 5` and `y = 12` and see if you get the same results as Problem #1.

Challenge: will all values of `||variables:x||` and `||variables:y||` make sense with this formula? If not, what constraints can we place on `||variables:x||` and `||variables:y||` to ensure that Tom a number of oranges that makes sense?

## Problem #4: Perfect PEMDAS Practice

For the following expressions, add parentheses to the equations to make the statements true:

Equation Equation
(a) `9` - `5` - `3` = `7` (g) `18` / `2` + `16` = `1`
(b) `13` - `3` - `7` = `17` (h) `12` - `6` / `3` = `2`
(c) `12` - `7` + `1` = `4` (i) `18` / `3` + `3` = `3`
(d) `6` + `2` * `12` = `96` (j) `18` / `1` + `5` - `2` = `1`
(e) `11` - `2` * `5` = `45` (k) `2` * `5` + `20` / `2` = `25`
(f) `16` + `13` * `3` = `87` (l) `6` + `15` / `3` + `1` = `8`

## Problem #5: Birthday Algorithm

Implement the Birthday Algorithm from CS Intro 1 in JavaScript:

Start with the variables `||variables:month||` and `||variables:day||` the both store numbers. Assign these values to a person’s birthday.

For each step below, modify a variable called `||variables:output||` that also stores a number.

1. Start with the number 7 (`let output: number = 7`)
2. Multiply by month the person was born (number 1 - 12)
3. Subtract 1
4. Multiply by 13
5. Add 5
6. Subtract 2
7. Add the day the person was born (number 1 - 31)
8. Multiply by 11
9. Subtract day the person was born (number 1 - 31)
10. Subtract month the person was born (number 1 - 12)
11. Divide by 5
12. Add 22
13. Divide by 200

When finished, `||game:game.splash||` `||variables:output||` to the screen.