Variables - Activity

Variables

Make sure you attempt the activity on your own before looking at the solution.

Instructions:

In your console write code to answer these questions:

  • How do you create a variable that holds the string 'Joe Smith'?
  • How do you create a variable that holds my favorite number, 9?
  • How do you create a new variable called goodNumber that holds the value 0?
  • How do you create a new variable and assign it the value of favNumber plus 4?
  • How do you reassign sum to be favNumber + 9?! An error! Explain that const stands for constant and indicates that the variable can't be reassigned.
  • How would you create a variable called product that holds the value one?
  • What needs to change if I want to reassign product to favNumber times two on the next line?
  • How can I set product equal to its current value times 4?
Solutions In your console write code to answer these questions: > "How do you create a variable that holds the string 'Joe Smith'?" 
const name = 'Joe Smith';
> "How do you create a variable that holds my favorite number, 9?" 
const favNumber = 9;
> "How do you create a new variable called `goodNumber` that holds the value `0`?" 
const goodNumber = 0;
> "How do you create a new variable and assign it the value of `favNumber` plus `4`?" 
const sum = favNumber + 4;
> "How do you reassign sum to be `favNumber` + `9`. This will error 
sum = favNumber + 9;
Uh-oh! An error! `const` stands for **constant** and indicates that the variable can't be reassigned. We should always use `const` when we can, but if we need to reassign a variable, we should use `let`. 
let bestNum = 0;
bestNum = 4;
bestNum = 3;
> "How would you create a variable called product that holds the value one?" 
const product = 1;
> "What needs to change if I want to reassign `product` to `favNumber` times two on the next line?" 
let product = 1;
product = favNumber * 2;
> "How can I set product equal to its current value times 4?" 
product = product * 4;
`product` on the right-hand side of the assignment operator refers to the value inside the `product` box. `product` on the left-hand side of the assignment operator tells the engine which box to store the new value in.