Introducing Hundredths
Age Range: 7 to 11
1) Draw a square on the board. Tell the children that you want them to think of that square as one unit.
2) Split the square into ten rectangular sections. Ask them what fraction of the unit each of these sections is worth (i.e. tenths).
3) Now split each of the ten sections into ten squares (there should now be 100 small squares inside the large square). Explain that we can split tenths up even more. The smaller sections are called hundredths.
4) Explain the following concepts:

There are ten hundredths in one tenths and one hundred hundredths in one unit.

Hundredths are written to the right of the tenths column when writing numbers in figures, i.e.
Units  Decimal Point  Tenths  Hundredths 
3  .  6  3 
9  .  5  2 

Hundredths are said in the following way:
7.53 = Seven Point Five Three (NOT seven point fifty three)
9.39 = Nine Point Three Nine (NOT nine point thirty nine)

4.70 is the same as 4.7. We don't have to write in the zero, but it is good practice to.
There are five followup activities which you might like to try when the children are confident with the above concepts.
A) Identifying Hundredths on a Number Line
This activity is based on worksheet (in PDF format only) here . Children should look at the number line and write in the table the numbers (in fractions and decimals) shown by each letter.
Answers (only shown in decimals) for this worksheet are:
A  B  C  D  E  F  G  H  I  J  K  L 
6.04  6.08  6.13  6.15  6.24  6.28  6.32  6.34  6.36  6.38  6.44  6.47 
M  N  O  P  Q  R  S  T  U  V  W  
6.52  6.60  6.63  6.66  6.72  6.77  6.80  6.83  6.87  6.94  6.98 
B) Counting Units, Tenths and Hundredths
Children will need to use the worksheet here and work out the values of the numbers shown in the pictures. Units are indicated by large squares, tenths by rectangles and hundredths by small squares. When they have worked out the value of each picture, they can write the answer (in figures and in words) in their books, or on the worksheet here.
Answers:
1) 3.63  2) 2.19  3) 2.43  4) 0.66 
5) 2.35  6) 3.07  7) 0.09  8) 1.27 
C) Which is Bigger?
This is a simple exercise which uses the worksheet here. It requires children to look at the pair of numbers in each row and decide which of them is bigger. They can indicate their answer by circling the larger number.
Answers are as follows: (larger numbers are underlined)
1.12 
12.14 
D) Sequencing Activity
Another simple exercise, which asks children to put a set of numbers in order (from smallest to largest). It can be found on the worksheet here. The correct answer is:
0.14  1.48  2.53  4.5  6.19  7.52  10.54 
E) Matching Exercise
This exercise (on the worksheet here) is similar to previous exercises involving tenths (see other pages in the decimals section). Children should fill in the blank spaces on the table, showing how numbers of the same value can be written in different ways. The completed table should look like this:
Fraction (words)  Fraction (figures)  Decimal (figures)  Decimal (words) 
6 units, 8 tenths and 9 hundredths  6 89/100  6.89  Six Point Eight Nine 
2 units, 7 tenths and 1 hundredth  2 71/100  2.71  Two Point Seven One 
3 units, 4 tenths and 2 hundredths  3 42/100  3.42  Three Point Four Two 
7 units, 9 tenths and 1 hundredth  7 91/100  7.91  Seven Point Nine One 
1 unit, 3 tenths and 4 hundredths  1 34/100  1.34  One Point Three Four 
1 ten, 9 units, 4 tenths and 2 hundredths  19 42/100  19.42  Nineteen Point Four Two 
8 units, 6 tenths and 4 hundredth  8 64/100  8.64  Eight Point Six Four 
9 units, 1 tenth and 2 hundredths  9 12/100  9.12  Nine Point One Two 
3 units, 0 tenths and 2 hundredths  3 2/100  3.02  Three Point Zero Two 
3 units, 4 tenths and 0 hundredths  3 4/10  3.4  Three Point Four 
If the children have completed the previous matching exercises, it is important to remind them that the rows in this table are not in order. The other tables went in numerical order (e.g. 1/10, 2/10, 3/10 etc). The numbers on this table are jumbled.
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