Secrets
Preparing for a multiplication quiz? Want to try out on the mathemagician team? Well here are some ways to do quick calculations!
Multiplication by 11
Whenever you multiply by 11 by a two-digit number try this:
11 x 34
Step 1: add 3 and 4 (3+4=7)
Step 2: place the sum in the middle (374)
Practice makes perfect (answers on bottom, don't cheat!):
1a) 11 x 16
2a) 11 x 18
3a) 11 x 45
But wait...there's more!
Suppose:
86 x 11
Even though 8 + 6 =14
It is NOT 8146
Instead the 4 (or units digit) goes in the middle, while the 1 (tens digit) adds unto the 8
So it is: 946
Practice:
1b) 11 x 69
2b) 11 x 48
3b) 11 x 99 (when revealing to a math teacher you are bound to be asked this)
11 x 34
Step 1: add 3 and 4 (3+4=7)
Step 2: place the sum in the middle (374)
Practice makes perfect (answers on bottom, don't cheat!):
1a) 11 x 16
2a) 11 x 18
3a) 11 x 45
But wait...there's more!
Suppose:
86 x 11
Even though 8 + 6 =14
It is NOT 8146
Instead the 4 (or units digit) goes in the middle, while the 1 (tens digit) adds unto the 8
So it is: 946
Practice:
1b) 11 x 69
2b) 11 x 48
3b) 11 x 99 (when revealing to a math teacher you are bound to be asked this)
Answers for Multiplication by 11:
1a) 176
2a) 198
3a) 495
1b) 749
2b) 528
3b) 1089
1a) 176
2a) 198
3a) 495
1b) 749
2b) 528
3b) 1089