General Math Strategies

Question 1

Doubling and Halving

Answer 1

If one factor is a multiple of 5 and the other number is even, DOUBLE the multiple of 5 and HALVE the other number

Question 2

Squaring shortcut - square multiple of 10

Answer 2

Square digit without the 0 and add 2 0’s at end

Question 3

Squaring shortcut - square multiple ending in 5

Answer 3

1) Remove 5, leaving remaining digit(s)
2) +1 to the digit, multiply digit with that sum (digit+1)
3) Put together product in front of -25

i. e. 25^2
1) 2+1 = 3
2) 2*3= 6
3) 625 = 25^2

Question 4

Finding squares through preceding/following integers

Answer 4

i.e. 41^2

Know 40^2=1600
So 41^2 = 1600+40+41 = 1681

OR OTHER WAY AROUND

i.e. 69^2

Know 70^2=4900
So 69^2= 4900-70-69=4761

Question 5

Dividing by 5

Answer 5

1) Double number

2) Divide by 10

Question 6

Backsolving

Answer 6

Helpful when all answer choices are numbers.

Choose answer C and plug into problem to narrow down answer options.