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63 Cards in this Set
- Front
- Back
- 3rd side (hint)
Front (Term)
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odd formula
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= 2n+1
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even + even
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even
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even + odd
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odd
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odd + odd
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even
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even x even
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even
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even x odd
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even
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odd x odd
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odd
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Irrational number
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non-terminating or non - repeating ex. 3.14752….
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Rational Number
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Terminating fraction or repeating fraction ex. 2.15 , 2
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Prime Number
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Number with exactly two distinct natural number divisor : 1 and itself
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Composite number
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Number with more than 2 factors
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First 26 Prime
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2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 83 89 97 101
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All prime number end in 1,3,7,9
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How to Verify Prime
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Check N > divide N by all integer number smaller than Root N ex. root161 is little less than 13 so we divide 161 by 2-13 .. 161 is divisible by 7 so its not prime
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proper divisor
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positive divisor of n which is different from n
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perfect number
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when sum of proper divisor is equal to the number itself
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Any positive divisor of n is a product of prime divisors of n raised to some power
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If a is a factor of b, b is a factor of a.. what is the relationship
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a=b or a=-b
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If a is a factor of bc, gcd(a,b)=1,
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then a is a factor of c เพราะแปลว่า a หาร b ไม่ลงตัว
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If p is a prime number and P is a factor of ab |
then P is a factor of a or P is a factor of b |
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Greatest Common Factor
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GCD หารร่วมมาก แยกตัวประกอบแล้ววงตัวที่ซ้ำกันมาคูณกัน
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Lowest Common Multiple
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LCM
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ดึงตัวประกอบร่วม คูณตัวที่เหลือ
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a x b = GCD(a,b) x LCM(a,b)
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perfect square
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Integer written as the square of some other integer. 16=4^2
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Divisible by 3
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If the sum of the digits is divisible by 3
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Divisible by 4
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last two digit หารลงตัว
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divisible by 6
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3 กับ 2
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divisible by 7
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last digit x 2 - ตัวที่เหลือ หารลงตัว
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divisible by 8
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last 4 digit divisible
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divisible by 9
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same as 3
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Trailing Zeros
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125000 has 3 trailing zeros
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sum of n consecutive integers equals
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the mean multiplied by the number of the term
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If n is even, sum of consecutive integer |
is never divisible by n
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If n is odd, sum of consecutive integer |
If n is odd, sum of consecutive integer is always divisible by n
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The product of n consecutive integers is .. |
The product of n consecutive integers is always divisible by n!
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Evenly spaced set
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sequence that difference of any two successive member of the sequence is constant >> An= A1+d(n-1)
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Mean&Median of evenly spaced set
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Mean is equal to median = (A1+An)/2
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Sum of evenly spaced set
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mean x n
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sum of n first positive integers
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1+2+…+n = (1+n)/2 x n
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sum of n first positive odd numbers:
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a1+a2+…+aN = n^2
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e.g. 1,3,5,..
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sum of n first even numbers :
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a1+a2+…+aN = n(n+1)
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e.g.. 2,4,6,..
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If the evenly spaced set contains odd number of elements, the mean is the middle term.
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so the sum is middle term multiplied by number of terms.
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proper fraction
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0
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improper fraction
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can be written as mixed number
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Mixed number
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4 3/5 or 23/5
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reciprocal of x
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1/x or x^-1
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√2
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1.41
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√3
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1.73
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√5
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2.24
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√6
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2.45
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√7
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2.65
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√8
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2.83
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√10
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3.16
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Percentile
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If someone’s grade is in xth percentile of the n grades, this means that x% of ppl out of n has the grade less than this person
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Front (Term) |
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Front (Term) |
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Front (Term) |
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Sum of squares of 1st n consecutive natural nos
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n(n+1)(2n+1) / 6
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Sum of cubes of the 1st n consecutive natural nos.
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[n(n+1)/2]^2
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Sum of all consecutive integers:
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N (N+1) / 2
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SUM OF EVEN NUMBERS:
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N(N+1) ;n= จำนวนพจน์
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SUM OF ODD NUMBERS:
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N^2 ; n= จำนวนพจน์
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