# Numbers

## Numbers are our way to quantify, label, and organize the world around us in a logical manner. However, the systems used to obtain this goal differ geographically, historically, and by relative utility. All questions pertaining to numbers, including historic labeling systems, bases of numerical systems, constants, and the various ways they're grouped together, should be placed into this category.

### Are there any even prime numbers other than two? No, the number 2 is the only even prime number. All other even numbers (4, 6, 8, etc.) are divisible by 2. (This is due to the definition of an even number as divisible by 2.) Thus, 2 is the only even number that can still be prime - the rest have at least one divisor other than 1 and themselves.

### What is XXXVIII in Hindu- Arabic numbers? XXXVIII = 38 The hindu-arabic numeral system can be found in related link (pictures), as I cannot put pictures here.

### How do you enter an imaginary number in a scientific calculator? Some scientific calculators can't handle complex or imaginary numbers. If you happen to have a special calculator that does, probably the manual will tell you how to enter them. The HP 48 and up series does. It depends on if your calculator is in Polar Coordinate mode or X-Y coordinate mode, but a quick way to get the imaginary number i (regardless of which mode the calculator is currently in), is to press -1, then 'square root' button.

### How do you write 60 million in number form? Something that is a million starts on the left of 6 digits before the decimal point. For instance, 1 million is 1,000,000.0. Then, 60 million in number form is: 60,000,000

### What are the shared prime factors of 36 and 144? 2 and 3. In fact, 2 and 3 are the ONLY prime factors of both. 36 = 22 x 32. 144 = 24 x 32.

### How much is 10 raise to power -15? 10 to the power of -15 is 1/10^15. (1/1,000,000,000,000,000 [15 zeroes]) It can also be written as 0.000000000000001 (There are 15 zeroes). OR -1,000,000,000,000,000 (15 zeroes).

### Prime numbers up to 200? 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 101 103 107 109 113 127 131 137 139 149 151 157 163 167 173 179 181 191 193 197 199

### What numbers add up to make 666? ### What is 40 cubed? To cube a number means simply to multiply that number by itself 3 times. To work out 40 cubed you would simply go: 403 = 40 x 40 x 40 40 x 40 = 1,600 1,600 x 40 = 64,000 403=64,000 Therefore, 40 cubed equals 64,000. The phrase "multiply that number by itself 3 times." can cause confusion. Sometimes, instead of multiplying it thrice (the number itself) others, due to confusion, just multiply the number by 3... take note it's cube... What do you get if you multiply 40 by itself once? Nearly everyone would say 1,600 which is 40². Multiply that by 40 then seems to mean multiply the answer by 40, giving 64,000 which is then 40 multiplied by itself twice! Of course some people will say it doesn't matter how many times you multiply 40 by itself you'll always get 1,600. Just think of 40³ as meaning 3 40s multiplied together and you should avoid any problems.

### What is the fraction 8 over 25 as a percent? To convert a fraction (or decimal) to percentage, multiply by 100, thus: 8/25 = 8/25 x 100% = 32%

### What two numbers squared equal a perfect square? 32+42=52 9+16=25 You can keep this pattern going, too: 3² + 4² = 5² 6² + 8² = 10² 9² + 12² = 15² 12² + 16² = 20² And so on and so forth...

### Is 0.2 with a horizontal line over it greater than 0.2 without the line? Yes, the bar over the 2, means that the digit (or digits) are repeated forever. so 0.2 (with bar over 2) = 0.2222222222..... is decimal for 2/9 (fraction) and 0.2 (no bar) = 0.200000000 which is 2/10 you could look at it a few ways. 0.2222222.... = 0.2 + 0.0222222.... which is greater than 0.2 or compare 2/9 & 2/10, 2/9 = 20/90 & 2/10 = 18/90 with the same denominator 20 > 18, so 2/9 > 2/10

### What is a decimal of 140 percent? The percent sign % can be defined as "divide by 100". So the decimal of 140% would be 140/100 or 1.4 So if you wanted to know what 140% of any number was you could multiply by 1.4 i.e. 140% of 50 is 50 x 1.4 = 70, or since multiplication is distributive you could also do this (140 x 50)/100 which will also give you 70 1.4

### When the lesser of two consecutive integers is added to three times the greater the result is 43 Find the integers? Let the two integers be m-1 & m, so the lesser integer is m-1, and the greater integer is m: (m-1) + 3*m = 43 --> 4*m -1 = 43 --> 4*m = 44, m = 11 & m-1 = 10, so 10 & 11 Check: 11 times 3 is 33, add 10 is 43

### Is 55 an even number? no because a full number would be divisible by 2, in this case it is not. Hints: If the final digit is odd the full number is odd. If it is even or 0, the whole number is divisible by 2: if 0 the answer will end in 5.

### What does the word product mean in math? When you multiply, your answer is called a product. In math, the word "product" implies multiplication. If you are asked to find the product of two numbers, you should multiply them together. So the product of 3 and 4 would be 3*4=12 Product is the answer you get when you multiply Example:2×6=12,so 12 is the product