Lesson 6
Let's see how to multiply proper fractions.
| Let's find a method for calculating |
3 |
× |
5 |
. |
| 4 | 7 |
Look at the picture above.
| The picture shows that |
3 |
of |
5 |
is 15 times |
1 |
, which makes |
15 |
. |
| 4 | 7 | 28 | 28 |
The total number of pieces in the area pictured is 4 × 7 = 28, which represents the whole. The number to find for the 3/4 of 5/7 proportion is: 3 × 5 = 15.
| 3 |
× |
5 |
= |
3 × 5 |
= |
15 |
| 4 | 7 | 4 × 7 | 28 |
| The figure below represents expressions like |
3 |
× |
5 |
= |
3 × 5 |
: |
| 4 | 7 | 4 × 7 |
115
| What are some ways to multiply |
3 |
× |
8 |
? |
| 4 | 9 |
| | 2 | |
| 3 |
× |
8 |
= |
3 × 8 |
= |
24 |
= |
2 |
| 4 | 9 | 4 × 9 | 36 | 3 |
| | 3 | |
| | 1 | | 2 | |
| 3 |
× |
8 |
= |
3 |
× |
8 |
= |
2 |
| 4 | 9 | 4 | × | 9 | 3 |
| | 1 | | 3 | |
| | 1 | | 2 | |
| 3 |
× |
8 |
= |
3 |
× |
8 |
= |
2 |
| 4 | 9 | 4 | 9 | 3 |
| | 1 | | 3 | |
Multiply the following fractions.
Angela filled a watering can with 2/3 liter of plant food. She used 3/5 of the plant food on her plants. How many liters of plant food did she use?
