What are arithmetic progressions?

An arithmetic progression is like counting stairs, each step goes up by the same number.

Imagine you're climbing a staircase where every step is 2 inches taller than the one before. That's an arithmetic progression: a sequence of numbers that increase (or decrease) by the same amount each time. You start at a certain point, and then you add or subtract the same number again and again.

Let’s say you're baking cookies, and every minute you take out 3 more cookies from the oven. If you started with 2 cookies, after one minute you have 5, then 8, then 11… That’s an arithmetic progression too! The number of cookies increases by 3 each time, that's your common difference.

Let’s try this: start at 4, and add 2 every time. Your sequence would be:

• 4
• 6
• 8
• 10
• 12

That’s an arithmetic progression with a starting number of 4 and a common difference of 2.

You see them everywhere, in stairs, in time, in cookies. Just remember: it's all about adding or subtracting the same amount each step! An arithmetic progression is like counting stairs, each step goes up by the same number.

Imagine you're climbing a staircase where every step is 2 inches taller than the one before. That's an arithmetic progression: a sequence of numbers that increase (or decrease) by the same amount each time. You start at a certain point, and then you add or subtract the same number again and again.