Astaircase has 105 blocks, how many stairs does it have?

11
23
36
410
515
621
728
836
945
1055
1166
1278
1391
14105
15120
16136
17153
18171
19190
20210
21231
22253
23276
24300

here is a spreadsheet to help you understand the stair problem notice for 1 step 1 block, 2 step, 3 block, 3 step, 6 block and so on notice the blocks for the number of a step is that step plus all the other blocks needed to make all the one(s) below it. Notice it takes 105 blocks to make 14 steps.
So if you are familiar with the summation process you would add the number that go with that stair with all the stairs below it. example step 5 blocks would be 5 + 4 + 3 + 2 +1 or 15 blocks. I hope this gets you started. The second part I do not understand the problems because they are not equations. NO equal signs

glad if it helps