虽然这里要列出的是要熟练记住的， 但是我从来都不鼓励死记硬背。 相反，记忆的过程中我觉得应该鼓励小朋友掌握和理解背后的规律更重要。所以我在列这些常识时，会尽量列出帮助记忆的办法，也就是背后的数学规律。

Prime numbers between 1 and 100:
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97.
A prime number is a whole number that only has two factors which are itself and one. A composite number has factors in addition to one and itself.
The numbers 0 and 1 are neither prime nor composite.
All even numbers are divisible by two and so all even numbers greater than two are composite numbers.
All numbers that end in five are divisible by five. Therefore all numbers that end with five and are greater than five are composite numbers.

Perfect Squares 121:
number square square root 1 1 1.000 2 4 1.414 3 9 1.732 4 16 2.000 5 25 2.236 6 36 2.449 7 49 2.646 8 64 2.828 9 81 3.000 10 100 3.162 11 121 3.317 12 144 3.464 13 169 3.606 14 196 3.742 15 225 3.873 16 256 4.000 17 289 4.123 18 324 4.243 19 361 4.359 20 400 4.472 21 441 4.583 
Common Fractions with Decimal and Percent Equivalents
http://www.factmonster.com/ipka/A0876706.html
Fraction Decimal Percent 1/2 0.5 50% 1/3 0.333… 33.333…% 2/3 0.666… 66.666…% 1/4 0.25 25% 3/4 0.75 75% 1/5 0.2 20% 2/5 0.4 40% 3/5 0.6 60% 4/5 0.8 80% 1/6 0.1666… 16.666…% 5/6 0.8333… 83.333…% 1/8 0.125 12.5% 3/8 0.375 37.5% 5/8 0.625 62.5% 7/8 0.875 87.5% 1/9 0.111… 11.111…% 2/9 0.222… 22.222…% 4/9 0.444… 44.444…% 5/9 0.555… 55.555…% 7/9 0.777… 77.777…% 8/9 0.888… 88.888…% 1/10 0.1 10% 1/12 0.08333… 8.333…% 1/16 0.0625 6.25% 1/32 0.03125 3.125%