Skip to main content

Using Legos To Provide A 3D Visual On Using Block Diagrams To Solve Primary 3 Arithmetic Problem Sum

Boys usually learn faster if they are hands on and can visualise the problems. As such, I usually use Legos to explain maths concept to my son so he can visualise the working and the solution.

Last night, we were going through the maths homework and there was this arithmetic problem sum that required the understand of the concept of units. It only dawned upon me in the morning after how I could have used Legos to explain the concept to him, which I will be showing him later today.

The Problem Sum

There are three fishes. Fish A cost three times as much as Fish B. Fish C cost $4 less than Fish B. The total cost of the three fishes is $46. Find the cost of Fish A. 

Step 1: Compare cost of Fish B and Fish A.

Let's take the 1-whole Lego block to represent the cost of Fish B.



Since Fish A cost three times as much as Fish B, the cost of Fish A cost 3 x 1-whole Lego Block.


Step 2: Compare cost of Fish B and Fish C

 As Fish C cost $4 less, let's the 3/4 Lego block to represent the cost of Fish C.


The $4 difference can be presented by the 1/4 Lego Block.

Step 3: Cost of 1-whole Lego Block

To find the cost of a 1-whole Lego Block, I will need to the cost of Fish B to be represented by a 1-whole Lego Block. This will then allow me to take the Total Cost of the Fishes to be presented by 5 x 1-whole Lego Blocks and I can divide this Total Cost by 5 to find out the cost represented by 1-whole Lego Block.

However, the cost of Fish C is short of a 1/4 Lego Block (=$4). As such, I have to add the 1/4 Lego Block to Fish C to make it a full 1-whole Lego Block.

If I add 1/4 Logo Block to Fish C, I would also need to add 1/4 Logo Block to the total cost.

Since the 1/4 Logo Block = $4, I add $4 to the total cost of the Fishes which is now $50.


Step 4: Determine the value of 1-whole Lego Block

The value of 1-whole Lego Block can be determined now by $50/5 = $10.

Since cost of Fish B is represented by 1-whole Lego Block, Fish B cost $10.

Step 5: Calculate the cost of Fish A

As the value of Fish A is represented by 3 x 1-whole Lego Blocks, cost of Fish A is $10 x 3 = $30.

The question could also ask to find of cost of Fish C. To do this, simply take $10 - $4 = $6 as from the block diagrams.
Labels:

Comments

Post a Comment

Popular posts from this blog

Primary 3 Level 2 Maths Money Problem Sum

Below is a money problem sum for Primary 3. It isn't that difficult to solve when you under the basic approach. Mr Lim went to watch "Disney on Ice" with his two sons. He paid $147.50 for all the tickets. A child ticket cost $30.50 less than an adult ticket. How much does a child ticket cost? Child tickets are of equal parts and the adult ticket is $30.50 more than 1 child ticket. So to make the Adult ticket to be of equal parts with the Child ticket, you have to take away $30.50 from the Adult ticket. If you do this, you also have take away $30.50 from $147.50. $147.50 - $30.50 = $117 All of the 3 parts are now equal and the sum of the 3 parts is $117. So you just take $117 divide by 3. $117 ÷ 3 = $39 As such, each child ticket is worth $39. There could be some variations where question ask for the total of two child ticket which you take $39 x 2 = $78 or your child will be asked the price of the adult ticket which is $39 + $30.50 = $69.50.
Post a Comment
Read more

Chicken And Rabbit Maths Question

They call it the Chicken and Rabbit maths question. The question will start with the total number of chicken and rabbit, and the total number of legs. With this, you be asked how many chicken there are in the farm. The chicken and rabbit can be replace with any two and four legged animal respectively. Example of question - Hussain saw a total of 23 sheep and ducks in a farm. If there are total of 82 legs, how many ducks did he see? Many parents will look to algebra to get the answer. Eg x=sheep, y=ducks, so x+y=23 and 4x+2y=82. As this is P3 maths, you are technically not allowed to use algebra as it is not taught yet and algrebra is Mathematics and not Arithmetic. The other method is to do ratios but it can be a challenge if the numbers get too big.  I found a Youtube Video which explains how to this sum but I am blogging this to keep a record on how to this for posterity. The Explanation and The Working  There are a total of 23 animals in the farm and ...
Post a Comment
Read more

Parent Sues Singapore School To "Jail Break" Confiscated iPhone

My son had his wallet confiscated by his school principal once. I only asked him why it was confiscated but didn't go to the extend of calling the school to get his wallet return, let alone thinking of suing the school.  However, a parent in a well known school in Singapore got wind of his son's iPhone being confiscated, as a result of using it during school hours, decided to sue the school after a call to the principle's office to "jail break" the phone was unsuccessful.  The lawyer for the parent argued that not returning the iPhone to the student "amounted to the tort of conversion" which in layman terms means "involves denying a person's rights to his property". Th Singapore courts decided that the case was "frivolous and vexatious". Lawyer argued that student did not enter a contract with the school but judge said that the school rules were well explained and if the parent had issues with the rules, should have...
Post a Comment
Read more