Decimal Shortcut Flashcards
1/2
0.5
1/4
0.25
3/4
0.75
1/3
0.3333
2./3
0.666
4/3
1.3333
1/5, 2/5,3/5,4/5
0.2,0.4,0.6,0.8
1/6
0.16666
5/6
0.83333
1/8
0.125
3/8,5/8
0.375,0.625
1/9,7/9
0.1111, 0.77777
Distance of x from origin
Absolute of x |x|
Distance of x from a number n
|x-n|.
Eg distance of 7 from 5 -> |7-5| =2
Distance of 7 from -5 -> |7+5| =12
Problem if
|x-1| =4 value of x?
The answer could be 4 units from the integer 1.
It could be both positive and negative
Hence, the answers are
1-4 = -3 and 1+4 = 5
Comparing fractions
If the denominator is the same, the fraction with greater numerator has greater value
If the numerator is the same, the fraction with the lower denominator will have greater value.
If the numerator gets bigger and denominator is smaller then that fraction is greater value eg 3/8 < 4/7
Comparing Fractions Hack
7/11 ? 5/8 this cannot be solved using tricks
Now using cross multiplication
78 ? 511
56 ? 55
56 > 55
Hence
7/11 > 5/8
When a numerator and denominator is added with same number, the number will move towards one
Eg 3/5 + 6/6 = 9/11
3/5 = 0.6
9/11 = 0.8
When numerator is lesser than denominator
Also,
7/4 + 1/1 = 8/5
7/4 = 1.7
8/5 = 1.6
This is when numerator is greater than denominator
Adding p to the numerator and q to the denominator
The fraction slides in the direction of p/q
If the original fraction is lesser than p/q, the result in a greater
If the original fraction is greater than p/q, the result is smaller
