Math Grade-3

Learning Objectives:

* Read and Write 4 - digit numbers.

A. Write the number names for the numerals.

1) 4501 = Four thousand five hundred, one

2) 7946 = Seven thousand nine hundred, forty - six

3) 8240 = Eight thousand two hundred, forty

B. Write the numbers for the number names.

1) Four thousand nine-one: 4091

2) Seven thousand three hundred fifty: 7350

3) Five hundred ninety- four 594

Successors and Predecessors:

The number that comes just after a given number is called its successor.

Number Successor

999 1000

3019 3020

* Add 1 to a number to get its successor.

The number that is just before a given number is called its predecessor.

Number Predecessor

201 200

3100 3099

* Subtract 1 from a number to get its predecessor.

Exercise :

A. Write the successor of each of the following :

1) 3129

2) 7034

3) 4119

4) 3089

B. Write the predecessor of each of the following:

1) 3260

2) 6001

3) 4100

* The sum of two odd numbers is an even number.

13 + 17 = 30

odd odd = even

* The sum of two even numbers is an even number.

24 + 12 = 36

even + even = even

* The sum of one odd and one even number is an odd number.

12 + 13 = 25

even odd = odd

* To find if a number is odd or even, divide the number by 2.

If the remainder is 1, the number is odd.

If there is no remainder, the number is even.

* There is an easier method of finding if a number is even or odd.

If a number has 0, 2, 4, 6, or 8 in the ones it is even.

If a number has 1, 3, 5, 7 or 9 in the ones place, it is odd.

Roman numerals:

It was invented by ancient Indian mathematicians. the Arabs learnt the system and passed it on to other countries. That is why the system is also called the Hindu-Arabic system. It is now used all over the world.

Long ago, the Romans had a different system of writing numbers. They used seven letters of the alphabet as basic symbols. These were used to write all numbers.

Roman numerals ______ I __ V X _ L __ C _ D M

Hindu-Arabic numerals 1 5 10 50 100 500 1000

Hindu - Arabic _1 2 3 4 5 6 __7 8 9 10

Roman I II III IV V VI VII VIII IX X

Rule 1 :

Repetition of the numeral means addition. However, it cannot be repeated more than three times.

Therefore II = 1 + 1 = 2

Rule 2:

A smaller numeral written to the left of a numeral of greater value means subtraction.

Therefore IV = 5 - 1 = 4

IX = 10 - 1 = 9

Rule 3: A smaller numeral written to the right of a numeral of greater value means addition.

Therefore VI = 5 + 1

= 6

Rule 4: Besides I, X can also be repeated three times, at the most. Repetition of X also means addition. V cannot be repeated.

Rule -5: For expressing numbers greater than 10, the numbers are first split in terms of tens and ones.

Fill in the blanks where necessary.

11 = 10 + 1 = X + I = XI
17 = 10 + 7 = X + VII = XVII
36 = 10 + 10 + 10 + 6 = X + X + X + VI = XXXVI

Word Problems:

1. Father bought a television set for $1232 and a steel cupboard for $1010. How much did he pay in all?

Cost of television set = $1232

Cost of steel cupboard = $1010

Total amount spent = $2242

Subtraction:

Q. When a number is subtracted from itself the difference is zero.

8349
- 8349
0000

Q. When '0' is subtracted from a number the difference is the number itself.

8349
- 0
8349

1. A shopkeeper earned $5078 and spent $3794 in a month. How much money was left with him?

Shopkeeper's earnings = $5078
Shopkeeper's expenditure = $3794
Money left with him = $ 1284

Math Grade-3

Successors and Predecessors: