Number Tricks Flashcards
1
Q
Multiply by 4
A
double twice
2
Q
Divide by 4
A
halve twice
3
Q
Multiple by 8
A
double three times
4
Q
Divide by 8
A
halve three times
5
Q
Multiply by 9
A
multiply by 10 and subtract the original number
6
Q
Multiply by 11
A
multiply by 10 and add original number
7
Q
Multiply by 99
A
multiply by 100 and subtract original number
8
Q
Multiply by 5
A
multiply a number by 10 then divide that answer by 2 OR divide by 2 then multiply 10
9
Q
Divide by 5
A
divide a number by 10 then multiply that answer by 2 OR multiply by 2 then divide that answer by 10
10
Q
Divide by 6
A
divide by 3 then divide that answer by 2
