Which number should come in place of the question mark?

The question is simple: look carefully at the row of numbers shown in the image and tell which number should come in place of the question mark.

Math puzzles like this help test your focus and logical thinking skills.
You just need to observe the pattern in the image closely and then find the answer.

As you can see, the sequence is 1, 3, 6, 10, 15, 21, ? now you have to find out what number should replace the question mark.

At first glance, it seems like an easy question, but the answer isn’t as simple as it appears.
So, what do you think the correct answer is?

Look at the pattern carefully, maybe you’ll be able to figure it out. And if it still feels tricky, here’s the answer: the number that comes in place of the question mark is 28.

If you notice, after 1 comes 3 (which means 2 is added), then comes 6 (adding 3), and so on — with each next number, one more is added than before.