How do I know by looking at the number 1,573 that it is evenly divisible by 13?
153978
For any number i (values for 1573 in parentheses): \ndefine i=10j+k (j=157, k=3)\nif j+4k (=157+12=169) is divisible by 13, then i is\n\nif you don't know if j+4k is divisible by 13, repeat the test on it, i.e.,\n(j=16, k=9, j+4k=16+36=52, is divisible by 13)\n\nSee the question, "number divisibility test?" for rationale and divisibility tests for other divisors.\n\nIn this case just dividing by 13 is quicker!  I don't how you can just look at it and tell.
951454
it is 178 * 177 !\n\nthis can always be computed.
1143446
I do both of those and I also test numbers for divisibility.  My car license plate has as its numeric part the number 594 which is divisible by 11, that's how I remember my license plate number.  Also, when someone asks me to pick a number between 1 and 10, I usually pick pi, phi, or e, just to be a smart@$$.  They didn't say an INTEGER between 1 and 10, did they???
343578
you search for a common factor, 2s,3s,5s and 10s are the most apparent. Once you look to a number you can immediately decide if it is divisible by 2 ( if the number is even) or by 3 (if the total of the digits is divisble by 3 i.e 168 total = 15 divisible by 3), or by 5 ( the last digit is 0 or 5) or divisble by 10 ( the last digit is 0).. good luck
584236
34\nsince 136 is divisible by 34.
67769
Divide 8 into 3\n.375
891593
ok look if the #, 538 last # is even then it is divisible by 2. And the rule for 3 is you add up all the digits 5+3+8=16, and if that #, 16, is divisible by 3 then the whole # is divisible by3. The rule for 5 is if the #, 538, ends in a 0 or 5. The rule for 6 is add up all the digits again 5+3+8= 16 and if 16 is divisible by 6 then the whole # is divisible by 6. And the rule for 10 is if the # ends in a 0!! \ngood luck
44369
There is an infinite quantity of numbers between 5/8 and 1/4
505203
The fractions you wrote are actually already reduced fractions; i.e. the gcd(numerator, denominator) = 1\n\nif you were intending to multiply the three fractions, that simplifies to 13/50
638209
1, 2, 3, 6, 7, 14, 21, 42
108159
lets say the fraction is 6/12\nfind a number that goes into 6 and 12 evenly\nin this case 2,3 and 6 do but you always go with the biggest number that can go into both.\nsix goes into itself once and into twelve twice so the answer is 1/2\nlets say the fraction is 13/6 its an improper fraction and needs to be reduced. thats the case when ever the top number is bigger then the smaller number.\ndivide the bottom number into the top number this time it goes in twice but you still have one left over. you put whatever is left over on top of your original bottom number and the answer is 2 1/6\n\nhope it helps
839757
Fifty-three nine hundred thirteenths.  You just read the number on top, then read the number on the bottom, change the ending just like you would if you were counting (the nine hundred thirteenth whatever), and add "s".
961314
easy the number is found as such \n\n21 = 3*7\n\n27 = 3^3 \n\n33 = 3 *11\n\n55 = 5 *11\n\nIn order that a number must be divisble by these, it must contain \nall factors. if you look for the samllest avoid repetition \n\n3^3 , 5, 11  =1385\n\nand you add 5 \n\nso the number is 1390
323032
13 times 13 equals 169
1116253
just divide both sides by 0.015...\n\nand you will get...\n\n566.66 \n\nwith a repeating six.
113980
Use a calculator - numerator divided by denominator will give you the answer.
90506
I'll take it as far as I can.\n\n3 - Add all the numbers and if the result is divisible by 3 then the entire number is 9+1+2+0+3+1+2=18 which is divisible by 3.\n4 - The last 2 numbers are divisible by 4. 12 is divisible by 4 so the entire number is.\n6 - It's divisible by 2 and 3.\n8 - If the last 3 numbers are divisible by 8, then the entire number is. 312/8=39. \n9 - Like for 3, except it has to be divisible by 9. The result, from above, is 18 which is divisible by 9.\n12 - If divisible by 3 and 4.\n18 - If divisible by 2 and 9.\n24 - If divisible by 8 and 3.\n36 - If divisible by 4 and 9.\n72 - If divisible by 8 and 9.