how do i find the sum of this arithmetic series? 10+20+30+....+110 +120 if you know a good youtube video or a website that explains this well could you tell me what it is? I have no idea what is going on in math class
each term is 10 more than the preceding term, so the difference is 10 the last term equals the 1st term plus 11 differences, so there are 12 terms 1st term plus last term equals 130 2nd term plus next to last term equals 130 this pattern is the same for for all six pairs of terms so the sum of the series is ___ 6 * 130