Tenths and Hundredths in whole Numbers

We will look today at converting decimal units

Decimals Warm Up (Flash player required)
Decimals Warm up 2

Imagine you were buying some chips that cost $2.40 but you only had 10c pieces.  Lots and lots of 10c pieces!  How many would you need to buy the chips?

If you think of 10c as a tenth of $1 then you could say that the number 2.4 is made up of 24 tenths.

How many tenths in each of these numbers?
1) 3.5                 2) 7.1              3) 12.5             4) 103.9             5) 12.51

Number 5 is a little odd:
12.51 has 125.1 tenths.

How many tens in all of the number
6) 140                   7) 1450               8) 132             9) 17.1         10) 7

Practice more of these on the socrative quiz that has been set up for you

If a scientist measures something, then accuracy is very important.  They often use small units like mm.

If a goatfish is 147mm long, how many cm exactly is it?

Convert these lengths
11)   125mm = ____ cm                                   12) 290mm = ____ cm
13) ______mm = 41.2cm                                  14) _____mm = 132.6 cm
15)  7mm = ____ cm

Now, find some objects in the class to measure.  Write down the precise measurement in mm and then convert this measurement into cm.
For example:

Pencil   125mm = 12.5cm