1. Lesson # 13 Squaring 5’s A neat shortcut… For multiplying
Numbers that end
With a 5,
Like 15, 25 , 35, 45…

2. In your head
Fairly
Quickly,
Hopefully, Hongbin!

3. Look at the first digit “1”.
Here is how it works…
Lets look at 15 x 15
It equals ?
Look at the first digit “1”.
Then, think of the very next digit, after a one…

4. It is a 2, right… Then what you do Is
multiply the 1 and the 2, together,
THEN
Put a “25” at the end of your answer.
Watch…

5. 15 x 15 =
1 x 2 = 2
Then stick on the 25…
225
Is the answer!
Trust me.

6. Another example…
95 x 95 = ?
9 x 10 = 90
Then stick on
the 25
9025

7. Remember…
All answers
End
With A
25 !

8. Now get ready to try 10
Practice Questions
Ready ?

9. Set ?
Go !

10. Question # 1
85 x 85 =

11. Question # 2
25 x 25 =

12. Question # 3
75 x 75 =

13. Question # 4
35 x 35 =

14. Question # 5
65 x 65 =

15. Question # 6
15 x 15 =

16. Question # 7
55 x 55 =

17. Question # 8
45 x 45 =

18. Question # 9
95 x 95 =

19. Question # 10
1.5 x 1.5 =

20. And now… get ready
To correct
Your
Answers !

21. Question # 1
85 x 85 =
7225

22. Question # 2
25 x 25 =
625

23. Question # 3
75 x 75 =
5625

24. Question # 4
35 x 35 =
1225

25. Question # 5
65 x 65 =
4225

26. Question # 6
15 x15 =
225

27. Question # 7
55 x 55 =
3025

28. Question # 8
45 x 45 =
2025

29. Question # 9
95 x 95 =
9025

30. Question # 10
1.5 x =
2.25

31. The
End

32. Did I mention…
Practice, practice, practice, practice, practice, Practice, practice, practice, practice, practice Practice, practice, practice, practice, practice Practice, practice, practice, practice, practice Practice, practice, practice, practice, practice Practice, practice, practice, practice, Practice, practice, practice, practice, practice practice ?