Challenge# 1

This is the first of the 100 challenges I am planning to post till the IMO exam for class 4. For each challenge a winner will be announced. The winner will have to answer the questions in the comment section.


Challenge 1

Q.1 Roshan entered the class at 9:30 AM. He attended three classes of 30 minute, 45 minute and 50 minute respectively before leaving the class. There was a break of 10 minutes between class 1 and 2. When did he leave the class ?

Q.2  A train takes 4 hours to travel from City A to City B. A bust takes 3 times as much time to cover the same distance. If the bust starts from City A at 4:35 PM when will it reach city B

Q.3 A book seller sold half of his books on Sunday, he sold 8 books on Monday. Now there are only 20 left . How many books were there when he opened his store on Sunday?

Q.4 You are 9th in a queue to buy tickets for a movie show. If each person takes 2 minutes to buy the ticket. How long will you have to wait to buy the tickets?

Q.5 What fraction of 70 is 30/100 of 50 ?

Divisibility rules

A number is divisible by

2 - If the last digit is even (0,2,4,6,8)
3 - If the sum of the digits is divisible by 3
4 - If the last 2 digits are divisible by 4
5 - If the last digit is 0 or 5
6 - If the number is divisible by both 2 and 3
7 - If you double the last digit and subtract it from the rest of the number and the answer is: 

• 0, or
• divisible by 7

8 - The last three digits are divisible by 8
9 - The sum of the digits is divisible by 9
10 - The number ends in 0
11 - If you sum every second digit and then subtract all other digits and the answer is:

• 0, or
• divisible by 11

12 - The number is divisible by both 3 and 4

Geometry - Cheat sheet

1. Acute Angle : An angle whose measure is between 0 and 90 degree
2. Obtuse Angle : An angle whose measure is greater than 90 but less than 180 degree
3. Right Angle : An angle whose measure is 90 degree
4. Straight Angle : An angle whose measure is 180 degree
5. An angle whose measure is 2 right angle is a straight angle
6. The sum of all angles of a triangle is 180 degree
7. An interior angle is an angle inside a shape
8. An Exterior Angle is the angle between any side of a shape, and a line extended from the next side
9. The sum of exterior and interior angle is 180 degree
10. The side opposite to the right angle of a right angled triangle is called Hypotenuse
11. The radius of a circle is half of its diameter
12. The radii of a circle will always have the same length. They start from the center of the circle and ends on the circumference of the circle
13. The diameter of a circle is twice the radius of the circle
14. A chord is a line segment   that joins two points on a curve. In geometry, a chord is often used to describe a line segment joining two endpoints that lie on a circle
15. Any portion of the circumference of a circle is called ARC
16. A chord that passes through the center of the circle is the diameter of the circle
17. Diameter is the longest chord
18. Every diameter is a chord but not every chord is a diameter
19. Every diameter will be of equal length
20. A line segment has 2 end points
21. A ray has one end point and no definite length
22. A line has no end points
23. Divider and scale are used to compare line segments

Prep for Class 4 Maths

1. At the bank, Mr Ghosh requested to withdraw a sum of Rs 98,500. He asks for the money in denominations of Rs 50 . How many notes does Mr Ghosh get ?


2. The distance between Bangalore and Hosur is 1234 KM. A bus makes 132 trips between Bangalore and Hosur . How much distance does the bus travel in all ?

3. How many Rs 500 note can Suman get from Rs 105,820. How much amount will be left?

4. To which number should 89 be multiplied to get 46,903

5. How many minutes are there in 2580 seconds

6. A fruit-seller bought 927,910 mangoes. He found that every 10th mango was rotten. After removing the rotten mangoes , he packed the remaining in 9 boxes. How many mangoes are there in each box

7. A factory in Chennapatna manufactures 340 toys in a day. How many toys the factory will manufacture in a year

8. The diameter of a circle is 20 cm. What is the length of its radius ?

9. The radius of a circle is 10 m. What is the diameter of the circle ?

10. One angle of a triangle measures 135 degree. What type of triangle is it ?

Mock test 2

The difference between the place value of 9 and 0 in 89055 is

A.900 
B.9009
C.9000
D.2000

Which of the following is meaningless

A.XV
B.XIX
C.IXIV
D.XXIV

The product of 2nd multiple of 9 and 12 is

A.108
B.18
C.81
D.216

Joyita read a 420 pages book in 6 days. She read the same number of pages in each day. How many pages did she read

A. 70
B.79
C.20
D.35

Smallest factor of a number is

A.0
B.1
C.the number itself
D.01

Find the missing number

2,4,8,32,256,?

A. 8192
B.9876
C.56
D.356

What makes a wholes

A. 2 Halves
B. 3 fourths
C. 5 thirds
D. 2 fourths

Mock test 1

I have prepared this short mock test for Jheel. Thought to share with all.

Mock Test - IMO 4

Try this out...

Last month Chota Bheem worked hard in the King's stable. He took good care of the horses . The King was very happy and rewarded Chota Bheem with 90 coins. That delighted Chota Bheem and he decided to buy some marbles with those coins. He went to the market and asked the shopkeeper to give him marbles in exchange of the 90 coins. The shopkeeper said

"Bheem, one marble will cost you Rs 5 but I will give you 50% discount on every fifth marble"

Now tell me how many marbles could Chota Bheem buy from the shopkeeper.

International Math Olympiad Class 4 - What is the format

One of my friend today asked me what is the format and pattern of the IMO paper for Class 4. I explained the format and pattern to him. I thought it may be useful to other parents as well.

International Mathematics Olympiad for Class 4

The test paper has 35 questions in all. You will get 1 hour(60 minutes) to answer all questions. The question paper will have 4 sections.

Section I : Logical reasoning - There will be 10 questions in this section
Section II: Mathematical Reasoning - There will be 10 questions in this section
Section III : Everyday Mathematics - There will be 10 questions in this section
Section IV : Achievers Section - There will be 5 questions in this section

What topics should you focus

Numerals and write in figures(5 digit numbers)
Place value
Roman Numeral
Addition and Subtraction problems
Geometry
Multiplication and division problems
Factors and multiples
Fractions
Measurement
Data representations through bar charts
Money problems
Time
Weight and capacity
Number series and patterns
Conversions Kilometer to Meter, Rupee to Paise etc
Comparison
Calculation of perimeter for various shapes
Direction sense
Mirror images
Embedded figures
Number ranking
Decoding and coding
Symmetry
Mathematical reasoning

That's all I have to share today. In my next post I will share a bank of questions on each topic





 

Online mock test - IMO Class 4...

I am conducting an online mock test for IMO Class 4 on 30th August. Please send your email to me if you are interested to be part of the test. Send email to joyasree78@gmail.com

Now solve this

A toy elephant costs Rs 25 more than a toy horse. The sum of the price of a toy elephant and a horse is Rs 75. What is the price of toy elephant ?

Hint : what we do not know is denoted by variables (e.g x)

Algebra - Session 2

One day Chutki came running to Bheem. She was exhausted and breathing heavily.

A surprised Bheem said " Hey Chutki what happened, why are you running ?"
Chutki said "Oh Bheem I have made a huge mistake. My mother told me to prepare the ladoo mixture today . I mixed flour and sugar together and now I forgot how much sugar did I add. I had 10 kg of flour and mom told to add only 5 kg of sugar to it. I know you are intelligent. Please help me here else I will be beaten up by mom".

Bheem smiled and said, "Chutki calm down. Let us analyze the problem. Tell me what is the total weight of the flour and sugar mixture now"

Chutki told "Wait , let me measure...oh it is 14 Kg"

Bheem then took a board and started writing on it

Weight of flour = 10 Kg ( Chutki knew this)
Total weight of the mixture = 14 Kg( Chutki also knew this)
Weight of sugar = x Kg( this is the variable which is not known)

So, we can write

weight of flour + weight of sugar = 14 Kg
10 + x = 14

In the above equation, to know the value of x, we will need to get rid of 10. How do we do it? We just substract it from 10 to make it zero as below

10 + x -10 = x

but we will need to do the same thing to the right side of the equation as well. So we will need to substract 10 from 14 as well. It therefore will look like

10 + x -10 = 14-10
x + 0 = 4
x = 4

So, Chutki added 4 kg of Sugar, she will need to add 1 more to make the mixture

Finding out the solution, Chutki was very happy. She thanked Bheem and ran home to prepare the ladoos.


 

Algebra - Session 1

Let us talk about equations today

An equation is a mathematical statement where 2 expressions are equal

4 + 5 = 9 is an equation.

We can also make equations using variables. For example let us consider the below statement

The sum of the price of a mango and an apple is Rs 30.

In the above case, we do not know the cost of a mango or an apple. They are unknowns and will vary based on what price is decided for an apple or an orange. Let us assume the price of apple is Rs x and price of mango is Rs y. Then we can make an equation as below

x + y = 30 (because the price of an apple and a mango is Rs 30)

In the next session we will learn how to solve the variables using equations

Introduction to Algebra

One day Chota Bheem and Raju had a strong urge to eat ladoos. They decided to visit aunt Tuntun. Tuntun owns a ladoo shop. When they reached the ladoo shop, they saw that aunt Tuntun was busy making ladoos.

Bheem greeted aunt Tuntun "Good Morning aunt Tuntun"
"Good Morning Bheem, what are you guys upto", said aunt Tuntun
"Oh nothing much aunt, we are hungry. Can we eat some ladoos", said Bheem
Tuntun retorted, "Yes but there is a condition. You will have to explain me the concepts of algebra. I need to teach algebra to Chutki"
Bheem , as you know is an intelligent guy and mathematics is fun to him.
He said "Ok Aunt let us start from the basics. Do you know what is the difference between a constant and variable"
Tuntun said "No"
"Ok , let us learn it" said Bheem
Bheem then sat beside Tuntun and asked "Aunt , how many ladoos do you make everyday?"
Tuntun said "One thousand and fifty"
"Oh that's a lot", said Bheem. He again asked , "Is that number always the same, does it change ?"
"No, it is always the same ", said Tuntun
Bheem told " then that is called constant. A constant will always be a fixed value. So, in your case the number of ladoos that you make daily is always a constant"
"Now tell me, do you always have the same number of people visiting your shop", asked Bheem
"No, it always varies", said Tuntun
"Ok, so anything that does not have a fixed value, but may be assigned a value based on the need is called a variable or a literal", said Bheem

In Algebra, Constant and Variable are very important concepts

A constant always has a fixed value . For example 5,6,7,100, 99.78 all are constants
A variable does not have a fixed value, its value varies based on the requirement. In algebra we denote variables using letters like x,y,z,a,b,c etc.

Let us take an example to understand more

Tuntun makes 1000 ladoos daily , she sells a portion of those ladoos to her customers daily.

In the above statement , 1000 is constant but the number of ladoos sold is a variable( which can be denoted by x)

Number Patterns

Which number will be next

1. 10,17,26,37,?
2. 1,5,6,11,17,?
3. 9,64,125,?

How am I preparing my Kid for International Math Olympiads

I spent almost 1 hour daily during week days and 3-4 hours on weekends to prepare my kid for mathematics Olympiad. I am referring to the below books

1. BMA's Talent and Olympiad
2.MTG's IMO Workbook for Class 4
3. I have also prepared a series of questions from various other sources

I would like to hear from other parents on your approach to prepare your kids