i need help with maths unit changing like 20cm +100 km - 30 m=?

Question

i need some sites that will help me cuz i have a test on monday and i dont know how to change units i need to know things like...
20kg+ 20 g x 100t = or 20secx 100 hours - 100 min = and stuff like that please help
PLEASE HELLLPPPP

Answer 1

0.2 m + 100 * 10^3 m -30 m = 70.2 * 10^3 m = 70200 m

Answer 2

It is basically just memorizing how many cm in a m then in a km. Same with seconds to minutes to hours. The way I look at it, the easiest way is to set it up like this:

20cm = ? meters

1 meter
20 cm x --------- = 20 divided by 100, so .20m is twenty cm.
100 cm This way, you can tell the units cancel
out cm divided by a cm =nothing, so all you are left with is 1 meter. This way works for every type of conversion problem. I am using it as a senior in college to find chemical concentrations, energy usages, and it is the same exact eqn.

another one: 20 seconds to hours
1 min 1 hr
20 sec x --------- x ---------- = ~.0056 hr.
60 sec 60 min

All you do is break it down into sections and make sure all of the units you don't want cancel out. sec/ sec and min/min both cancel out. leaving you with an hour. As for the math, it is just 20 / 60/60 and you get the numerical part of the answer.

**Once you break it down to all the same units, you can add or subtract them like any other number, and stick the units at the end. If you end up with 2 units, such as grams and seconds, it is just where they are on the equation, if grams is on top and seconds on the bottom, it would be grams/seconds, or if both of them on top it would be grams-seconds
Hope this helped!

Answer 3

what you are doing when you change units is multiplying by one. You need to know the equivalents though

1 meter = 100 cm
1km = 1000 meters

so say we have

1 meter + 50cm + 2km = (in meters)

so from the above we know

1 meter = 100 cm and since the answer is in meters we want to get rid of the cm. So,

1meter/100cm = 1

also

1000 meters = 1 km

1000 meters/km = 1

next we multiply these two with the nesecary parts of the equation and cancel like terms:

1 meter + 50cm*(1meter/100cm) + 2km*(1000 meters/km)
we can now multiply the numbers and cancel the cm on top with the cm on bottom. We do the same with the km on top and bottom.

now everything is in meters so we can just add.

1 meter + .5 meter + 2000 meter = 2001.5 meters

Answer 4

hey it is so easy just remember it

1 kg = 1/1000 gm , 100kg= 1 t


1 km = 1/100 meter
= 1/1000000 cemtemeter

1hour = 60 min
= 3600 sec


1) fist doen maltifistion & divistion .
2) then doen eddistion & subtrestion. ( with right hend said ruls)

~~> if u wont 2 give answer in m.k.s unit ( standerd from )

then ~~> 20 kg+ 20gm x 100 t

convart in gm to kg 20gm = 20/1000
=0.002
now convart tun in to kg 100t= 100x100
=10000

now put the value = 20kg + 0.002 kg x 10000kg

now 1st rul doen malti or divistion so ( 0.002x10000=100)
so =20 kg + 100kg
=120 kg ans......


(2) 20 cm+ 100km -30 m
all convart in km 20 cm = 20/1000000
= 0.000002
30 m = 30/100
= 0.03
so ans is 0.000002 km + 100 km + 0.003 km=100.03002 km .....
if u wont 2 giv answer in meter then convert the km into meter so km / 1000 so it is form of meter , & convert cm into meter so cm x 1000 so it is from of meter
i think u understand it...

if u chang the hour into sec then hour x 3600
hour into min hour x 60

Answer 5

Here's one but it's kind of complicated:
http://oakroadsystems.com/math/convert.htm

Just try to convert to the smallest of all the units. That way you won't have to worry about fractions or decimals.

Answer 6

Google calculator. Just go to www.google.com, and search for your math problem, the answer will display above the search results.

Answer 7

Try these:
http://www.digitaldutch.com/unitconverter/
http://www.chemie.fu-berlin.de/chemistry/general/units_en.html
http://en.wikipedia.org/wiki/Conversion_of_units

Good luck!