Miss Kashef here — let's make math faster and easier in your head!
Slide 1 of 10
🧠⚡
Mental Math Strategies
Hello my clever Grade 3 friends! Today Miss Kashef will teach you smart ways to do math in your head using properties of operations. This will help you calculate quickly and confidently without always needing paper!
Commutative Property
You can add or multiply numbers in any order and get the same answer.
3 + 5 = 5 + 3 = 8
4 × 6 = 6 × 4 = 24
Associative Property
You can group numbers differently and the answer stays the same.
(2 + 3) + 4 = 2 + (3 + 4) = 9
(2 × 3) × 4 = 2 × (3 × 4) = 24
Making Tens (Friendly Numbers)
47 + 8 = 47 + 3 + 5 = 55
29 + 36 = 30 + 35 = 65 (adjust by 1)
Doubles and Near Doubles
6 + 6 = 12 (double)
6 + 7 = 13 (double + 1)
25 + 26 = 51 (double + 1)
Break Apart Strategy
48 + 35 = (40 + 30) + (8 + 5) = 70 + 13 = 83
67 - 29 = 67 - 30 + 1 = 37 + 1 = 38
Multiplication Mental Tricks
5 × 8 = half of 10 × 8 = 40
9 × 7 = 10 × 7 - 7 = 70 - 7 = 63
Practice Time!
58 + 7 = ?
45 + 39 = ?
You Are Doing Amazing!
You can now use properties of operations to do mental math quickly and accurately!
This makes you a faster and smarter mathematician.
Well Done, My Mental Math Wizards! 🌟
You have completed the full lesson on Mental Math Strategies.
Practice these tricks every day and you will become super fast at math!