math and arithmetic

math is the study of abstractions. math allows us to isolate one or a few features such as the number, shape or direction of some kind of object. then we can study what can be learned about the behavior of those features while ignoring everything else about the object.

1,148,388 questions

if you are 13 years old when were you born ?

you can calculate the year you were born if you subtract your age from the present year.

for example, if you are 13 years old, and it is currently the year 2020 , you were probably born in 2007 ; and if you are 13 years old in 2021, you were probably born in 2008.

how many 3s in 313433535333 ?

there are 18 - 21 three's depending on which picture you are looking at.

a farmer has 19 sheep all but 7 die how many are left ?

if you red the question carefully, you can see that it clearly says all but 7. so, 12 sheep died, leaving 7 left.

how many pennies in 600 dollars ?

there are 100 pennies in every dollar so 600 dollars would be 600x100, or 60,000 pennies.

how do you write 0.2 in word form ?

you could write "zero point two".

you could write "two-tenths".

9 times 8 ?

well if you really don't know it's 72 i learn in the 4th grade.

how many times does 3 go into 100 ?

100 ÷ 3 = 33.33 recurring.
or 100 ÷ 3 = 33 remainder 1.

how 1600 x 1600 pixels in inches ?

there is no way to give a real answer for that. pixels do not have a consistent size, so they can't be universally converted. pixels change size depending on the density of the thing displaying them (72 dots per inch is typical for screens and 300 dpi is typically selected for something that will be printed as form of quality photo). for screens size differs based on "pitch" of the screen(distance between two consecutive pixels) thus even small screens with low pitch value can display high resolutions!

however, to simply measure the width and height of your monitor at high accuracy just use the "jruler" application

download jruler from here:

how many times does 15 go into 100 ?

15 goes into 100 6 times with 10 as a remainder.

there is a bus with 7 children inside. each child has 7 bags. inside each bag there are 7 big cats. each big cat has 7 small cats. all cats have 4 legs each. how many legs are on the bus ?

as a riddle, the answer is zero legs on the bus since the bus has wheels instead of legs.

but as a maths problem; it's not a tricked question -- just a straightforward maths problem

confirmed answer is 10990 legs.

§ let's say the whole situation simply :

- there are 7 girls.

- each girl has 7 backpack

- each backpack has 7 big cats

- each big cat has 7 little small cats.

§ question: how many legs are there in the bus?

§ let's focus on each part of the question systematically, write down on a piece of paper if you have to, following my steps of chains.

1. focus on the first girl first:

a b c d e f g

girl a has 7 backpacks

2. now focus on first backpack a1 :

a1 a2 a3 a4 a5 a6 a7

backpack a1 has 7 big cats

3. now focus on first big cat :

1 2 3 4 5 6 7

ø each big cats have 7 small cats (that's the end of the focus)

systematically, 7 small cats has 28 legs (7 * 4) combined with the big cat that owns this 7 small cats.

let's call this the "cat chain", so cat chain 1 has 32 legs altogether.

ø so since there are 7 big cats

7 * 32 = 224 legs

ø therefore each backpack has 224 legs

ø finally, each girl has 7 * 224 = 1568 legs.

lastly, since there are 7 girls, a to g, there are 7 * 1568 legs (per girl) = 10976 legs.

now, since each girl also has 2 legs each;

so, ( 7 * 2) + 10976 = 10990 legs altogether

note: disregarding bus driver, buses and etc…only focus on the girl and their backpacks!


there are 7*7 = 49 bags and there are 7 + 7*7 = 56 cats in each bag, meaning there are 56*4 = 224 legs in each bag. so including the 7 children that have 2 legs each, there are 7*2 + 49(224) = 10990 legs in total.

can the denominator of a rational number be zero ?

josh mows lawns. he wants to pick up some customers but wants to know how long it will take before saying yes to all of them. he mows 3 of the lawns in 72 minutes. write an equation that will allow josh to calculate the time it would take to mow any given number of lawns.

math ?

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