Let's Get Mental
Mental Math
42+33 =
What is 75
50-10 =
What is 40
17 + 8 =
25
7 x 8 =
56
24/4
What is 6
Mental Math
7 x 7 =
What is 49
16-9 =
7
38 + 14 =
52
50 x 2 =
100
Mental Math
42 divided into 6 groups
What is 7
Mental Math
60 divided by 3=
What is 20
456-12 =
444
78 + 12 =
90
Double the number and add once more. What rule am I?
MENTAL MATH
40 divided into 5 groups
What is 8
Mental Math
30x20 =
What is 600
691 - _?_ = 52
639
1,234 + 2,345 + 4,567 + 7,890 =
16036
The four patterns for 9 trick
2. second digit count down
3. first digit is one less than what is being multiplied by 9
4. the sum of the two digits equal to 9
Steps for long division: Division Family
Mental Math
15x2 =
30
There are 67 bird families living near the mountain. If 32 bird families flew away for winter, how many bird families were left near the mountain?
35
Two boxes filled with comic books were just delivered. If each box is filled with 120 books, how many books are there?
240
The 0 trick (not 0 rule)
count the number of zeros at the end of a number and add in answer, then multiply like normal
3 rule: sum of the digits must be divisible by 3.
9 rule: sum of the digits must be divisible by 9.