Wednesday, May 27 — Day 10
Today's new things: 11/12 tables, 2-digit × 1-digit breakdown, Versailles.
Math
Add 11 and 12 to the memorized table:
- 11 × any single digit is "the digit twice": 11 × 4 = 44, 11 × 7 = 77.
- 12 × 12 = 144. 12 × 8 = 96. Memorize them all the way through 12 × 12.
Then the real move: 2-digit × 1-digit using the breakdown.
17 × 8 = (10 + 7) × 8 = 10×8 + 7×8 = 80 + 56 = 136.
You always split the 2-digit number into "tens + ones". Multiply each piece by the 1-digit number. Add.
Practice problems to do before the exam:
- 13 × 7
- 14 × 9
- 19 × 6
- 18 × 8
Science — valence row 3
Same pattern as row 2 (1 → 8 across the row):
| Element | Valence |
|---|---|
| Na | 1 |
| Mg | 2 |
| Al | 3 |
| Si | 4 |
| P | 5 |
| S | 6 |
| Cl | 7 |
| Ar | 8 |
Notice Na and Cl: 1 and 7. Na wants to give away its 1; Cl wants one more to make 8. They find each other → NaCl = salt. That's ionic bonding in one sentence.
History — Versailles, the bad one
Today: the WWI-era accords.
| Treaty | Year |
|---|---|
| Treaty of Versailles | 1919 |
| UN Charter | 1945 |
| Geneva Conventions | 1949 |
Versailles is the famous failure. The Allies punished Germany so hard — territory, reparations, blame clauses — that the German economy collapsed in the 1920s, the politics radicalized, and 20 years later Europe was back at war with worse weapons. Historians have argued ever since whether the treaty caused WWII directly or just set the conditions; either way it's the textbook example of "a peace deal that made the next war more likely, not less."
After 1945 the world tried to do it differently: the UN Charter created a forum for talking instead of just punishing; the Geneva Conventions set rules for how war is fought when it still happens. Neither one stopped war. But the comparison to Versailles is the point.
Today's exam (20 questions)
- 8 math (4 tables 11/12, 4 distributive 2-digit × 1-digit)
- 1 LCM + 1 fraction-add (review)
- 3 valence (row 3)
- 4 peace accords (Versailles / UN / Geneva + 1 Vienna review)
- 3 evolution (Cambrian set)
Warm-up
- 10 problems of the 2-digit × 1-digit shape, by hand.
- Read row-3 valence aloud.
- Read the three new years aloud once.