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JavaScript The Solution

Solution for Math Challenge

// 1. Attach this file -- math.js -- to the index.html file using a <script> tag

// 2. Add an alert to announce the program with a message like "Let's do some math!"
alert(`Let's do some math!`);
// 3. Create a variable and use the prompt() method to collect a number from a visitor
let num1 = prompt(`What is the first number ?`);
let num2 = prompt(`What is the second number ?`)

// 4. Convert that value from a string to a floating point number
let num1p = parseFloat(num1);

// 5. Repeat steps 3 and 4 to create a second variable and collect a second number
let num2p = parseFloat(num2);

// 6. Create a new variable -- message -- which you'll use to build
//    a complete message to print to the document
//    Start by creating a string that includes <h1> tags as well
//    and the two input numbers. The string should look something like this:
//    "<h1>Math  with the numbers 3 and 4</h1>" where the two numbers are
//    the values input from the user. Use string concatenation to create this
//    and make sure you actually perform the math on the values by 
//    using the + symbol to add their values together

message = `<h1> We will be using math operators on the two numbers of ${num1p} and ${num2p}</h1>

<h3> ${num1p} + ${num2p} = ${num1p + num2p} </h3>
<h3> ${num1p} - ${num2p} = ${num1p - num2p} </h3>
<h3> ${num1p} / ${num2p} = ${num1p / num2p} </h3>
<h3> ${num1p} * ${num2p} = ${num1p * num2p} </h3>
`;

// 7. Add another string to the message variable. 
//    The string should look something like this after concatenation:
//    "3 + 4 = 7"

// 8. Add a linebreak tag -- <br> -- to the message variable

// 9. Continue to add to the message variable to include strings
//    demonstrating multiplication, division and subtraction
//    For example:
//    "3 * 4 = 12"
//    "3 / 4 = 0.75"
//    "3 - 4 = -1"

// 10. Use the document.write() method to print the message variable 
//     to the web page. Open the finished.png file in this workspace
//     to see what the completed output should look like

document.write(message);

Should i have used var instead and is template literal the best way to right the message with out <br> ?

1 Answer

Steven Parker
Steven Parker
218,596 Points

For declaration, "let" is the more modern form and is generally preferable except where scope or hoisting needs make "var" advantageous. Neither of those apply here, so "let" is a good choice. But "const" is an even better choice when the value is not going to be changed later in the program.

Any heading element (like h3) is displayed in block mode, so it will be on a line by itself without using br. This is true no matter what method you output it with. Still, even though it deviates from the commented instructions, the single template literal makes the code compact and easy to read. :+1:

thank you trying to learn consistently day by day.

Do you have any articles or youtube videos which can elaborate more on how and what use-case would use the "var" , let or const keyword ??

Steven Parker
Steven Parker
218,596 Points

I'm sure any search engine will point you to several discussions on keyword choice, but for beginners, "const" will usually be the best choice for anything that won't be changed, and "let" for anything that will. They are both recent additions to the language, so you'll still see "var" used in older lessons.