Calculations and text

Computers are very fast at arithmetic, even with huge numbers. To make one calculate, write the sum inside console.log() without quotes. Anything inside quotes is text and is printed exactly as written:

console.log("1+1");
console.log(1+1);
console.log(1400 + 3600);

1+1
2
5000

Adding and subtracting use the usual signs, but keyboards have no × or ÷, so multiplication is * and division is /. There is a fifth useful sign: % gives the remainder of a division.

console.log(5 * 9);
console.log(10 / 2);
console.log(7 / 2);
console.log(17 % 5);

45
5
3.5
2

Just like in maths, *, / and % happen before + and -, and anything in brackets ( ) is calculated first. % is handy for checking even numbers: an even number divided by 2 leaves a remainder of 0.

console.log(2 + 3 * 4);
console.log((2 + 3) * 4);
console.log(10 % 2);
console.log(11 % 2);

14
20
0
1

Joining text with +

Put + between two pieces of text and it joins them into one text instead of adding. Watch the spaces: the computer never adds a space for you.

console.log("Today's lunch is " + "koshary.");
console.log("Good" + "morning");
console.log("Good " + "morning");

Today's lunch is koshary.
Goodmorning
Good morning

To put a result inside a sentence, use the pattern "text " + (formula) + " text". The brackets around the formula make the computer calculate it first, then join the result to the text:

console.log("Set of 2 coffees " + (250 * 2) + " pounds");
console.log("Set of 3 coffees " + (250 * 3) + " pounds");

Set of 2 coffees 500 pounds
Set of 3 coffees 750 pounds

console.log("Total: " + 2 + 3);
console.log("Total: " + (2 + 3));

Total: 23
Total: 5