In the last two lessons, you learned how to multiply by 0 to 5 and how to multiply by 6 to 9. You're doing great.
Now, let's learn how to multiply by 10 to 12.
10 × 6 = 60
To multiply a number by 10, just add a '0' at the end of the number.
Let's try it together.
10 × 9 = 90
10 × 3 = 30
10 × 7 = 70
Awesome! 🏄♀️
11 × 3 = ?
It looks hard at first.
Don't worry. There's an easy way to figure this out.
We know that:
11 = 10 + 1
So:
Multiplying by 11 = Multiplying by 10 + adding one more
Let's try it.
11 × 3 = 30 + 3 = 33
Great work! 👏
There's another trick for multiplying by 11.
To multiply 11 by a one-digit number, like 5, just double the digit.
11 × 5 = 55
To multiply 11 by a 2-digit number, add the two digits and put the sum in between the two digits.
Can you multiply 11 times 12 in your head, using the trick?
You just have to figure out 1 + 2. Then put that in between 1 and 2.
Can you figure out 11 × 45 in your head?
Way to go! 💃
12 × 4 = ?
Is there a trick? Yes.
We know that:
12 = 10 + 2
So:
Multiplying by 12 = Multiplying by 10 + Multiplying by 2.
Let's try it.
12 × 4 = 40 + 8 = 48
Very good.
Can you now find this answer in your head?
12 × 7 = ?
12 × 7 = 70 + 14 = 84
Tip: If you know 11 × 7 = 77, then you can also just add one more 7 to that to get 12 x 7.
12 × 7 = 11 × 7 + 7 = 77 + 7 = 84. ✅
Awesome.
The 10 to 12 times tables are given below.
Congratulations! 🎉 You now know how to multiply numbers by 10 to 12.
Start the practice below. It'll help you master the skill.