This is an exciting moment, friends! Today, we’re starting week 9 of the Solar System CAL, which is the *final *week of the base blanket!

Whew, right? It feels so good to finally be at the end of this massive blanket project–after this, it’s only fun stuff like Death Stars and space shuttles.

If you’re still catching up, that’s okay! You can find last week’s portion of the blanket pattern **here**.

**Rounds 105-106 took me approximately 2 hours to make.** Scroll down a little ways to see week 9’s section of the Solar System Blanket pattern!

A lot of you have tagged me in photos of your Solar System Blankets, and I just really love seeing your progress! Feel free to to tag Two Hearts Crochet on whichever social media platform you’re using, and remember to use #SolarSystemCAL! I absolutely love seeing all of your photos, so keep ’em coming!

*Ready for the final stretch? Of course you are, because you are SPECTACULAR!*

## Solar System CAL Week 9: Rounds 105-106

### VOID (continued) – In “MIDNIGHT” Color

Round 105) *hdc inc, hdc in the next 102 sts* x 6 (618 sts)

Round 106) *hdc inc, hdc in the next 103 sts* x 6. Join with a sl st to the beginning of the round and fasten off, leaving a tail long enough to weave in. (630)

**Please Note: Week 10 (more planets!) is available here.**

I feel like I am missing something. How did you come up with 60k+ stitches? I am doing 8 increases instead of 6 and by the time My base is done I will only have 46520 stitches not including the corona. What am I doing wrong?

I counted up the stitches of every round, so in reading the pattern that would start off like: 6+12+18+24+30… all the way up to the last round of the main blanket.

That being said, I’m terrible at math, so it’s possible I’ve added up my stitches incorrectly!

Out of pure curiosity (and having a mathematician-instructor for a husband), I checked the numbers and it should be 34,026 stitches on the base blanket. Here’s how:

If we have 106 rounds, and the sequence starts with 6 and increases by 6 with each round, then we have to add up 6, 12, 18, 24, 30 (like you said) and we go all the way up to 636. Each round is a multiple of six.

The formula to use to find the number of stitches done is 3n(n+1), where n is the number of rounds. So, if we have 106 rounds total, then the total number of stitches for the base blanket is:

3 x 106 (106 + 1)

318 x 107 = 34,026.

That formula is derived as follows. We’re looking for the sum of the first n multiples of 6:

S = 6 + 12 + 18 + 24 + … + 6n

= 6(1 + 2 + 3 + 4 + … + n).

The expression in parentheses is the sum of the first n consecutive positive integers. There’s a formula for that, namely [n(n+1)]/2. Thus our sum becomes

S = 6 + 12 + 18 + 24 + … + 6n

= 6(1 + 2 + 3 + 4 + … + n)

= 6 x [n(n+1)]/2

= 3n(n+1).

“It’s math-magical.” – my husband, everyone <3

Love this! Thank you for sharing!!