Use Properties of Multiplication

How the lesson starts: Use Properties of Multiplication

Ember's gem hoard
Hello, brave one! Ember is a friendly little dragon who loves counting gems. But big facts make her sneeze sparks! Today we learn her first trick: swap.
Turn the tray
Ember sets her gems in 3 rows of 7. That's 3 × 7 = 21. Now she turns the tray sideways. It shows 7 rows of 3. That's 7 × 3 = 21. Same gems, same total! You can swap the factors.
Which one matches?
Which has the same value as 4 × 9? Swap the factors: 9 × 4. Both make 36. Watch out for look-alikes! 9 + 4 is only 13. And 4 × 8 changed a factor, so it's 32. Only 9 × 4 matches.