My son is learning to convert lengths?

Question

He struggles with most maths problems. What is an easy way to explain the following :

10cm = ? m
200m = ? km
350cm = ? m

Thank you

Answer 1

Tell him to use the metric ladder:
km hm dam m dm cm mm
--------> when you go one unit right, divide the value by 10 each time.
<-------------------- when you go left, multiply the value by 10 each time.

That means 10 cm = 10/10/10 = 0.1 m (divided twice)
200m = 10/10/10/10 (divided 3 times)
350 cm = 3.5 m

TIP: When you divide by 10, you move the decimal place left one digit.
When you multiply by 10, you move it right.

Answer 2

I'd show him on a ruler how big a centimeter is if you have a ruler that shows metric. If you don't, get him to think of a centimeter as a little about 3/8 of an inch. Maybe think of his thumb as about one centimeter wide. Then show him a yardstick, and tell him that a meter is a little longer than that. Tell him that a kilometer is a little over half a mile. If he can relate the measurements to something he knows in the real world, might be a little easier.

As to the calculations to convert between cm, m and km, since that just involves moving a decimal point one way or the other, maybe you could just make up a simple "cheat sheet" for him to refer to for that, until it's second nature to him. When he sees "c" it means hundredths, so he has to move the decimal 2 places (number of zeroes in 100) to the left to convert to meters - if he's converting meters to cm, move to the right. "k" is thousands, so move 3 places.

Good luck to your son. The metric system is pretty easy since it's based on 10's, but can be real confusing to people who haven't grown up using the system, which USA doesn't.

Answer 3

Teach him first the following formula.

100 cm =1 m ----------------formula 1
1000m = 1 km ----------------formula 2

To solve 10 cm = ? m,Use formula one. Since in 100, two zero is there, for converting put decimal point before two digits from right side. i.e like0.10

In the same way for 350cm = ?m , answer is 3.50 m

For 200 m = ? km, use second formula.Since 3 zeros are in 1000, ask him to put decimal point before 3 digits from right. i.e. 0.200

Is it OK?

Answer 4

Tell yer that CGS system is just as good as any measuring system ther is or were, no reinvintation nesexeary either hare,
Waha, these would be : 0.01 m, 0.02 Km, 0.35 m