Learn the 5 properties of multiplication with examples: commutative, associative, identity, zero and distributive. For elementary and middle school with exercises.
The 5 properties of multiplication: Commutative: a×b=b×a. Associative: (a×b)×c=a×(b×c). Identity: a×1=a. Zero: a×0=0. Distributive: a×(b+c)=ab+ac.
Order doesn't matter. 4×6 = 6×4 = 24. Cuts memorization in half.
Grouping doesn't matter. (2×5)×6 = 2×(5×6) = 60. Group to make 10s.
Multiplying by 1 doesn't change the number. 7×1=7. One is the multiplicative identity.
Any number times zero equals zero. 999×0=0.
3×(4+5) = 3×4+3×5 = 27. Key for mental math and algebra.
See also properties of addition for the parallel rules with addition.
Buying 3 packs of 6 items = buying 6 packs of 3 items = 18 total. 3×6=6×3=18.
15% of $80: 10% of $80 + 5% of $80 = $8 + $4 = $12. Faster than 0.15×80 directly.
A rectangle with height 0 has area = 0, no matter how wide it is. L×0=0.
Yes. a×(b−c)=ab−ac. Example: 5×(10−3)=50−15=35. Same as 5×7=35.
It helps solve equations. If (x−3)(x+2)=0, then either x−3=0 or x+2=0, giving x=3 or x=−2.