Mathematics – Form 1

Chapter 1.2By Kelvin

SUBTRACTION OF WHOLE NUMBERS.

A) Subtraction1. Subtraction is a process of finding the difference

between two numbers. For example:- 65 - 20 = 45 (Difference or remainder)2. The difference between two same numbers is 0. For example:- 19 - 19 = 0

3. When we subtract 0 from a number, the number remains the same.

For example:- 75 - 0 = 754. Follow the steps below when carrying out subtraction. Step 1:- Arrange the numbers according to their place

values. Step 2:- Subtract or minus from right to left.5. Addition is the inverse of subtraction. For example:- 76 - 15 = 61 62 - 15 = 47

B) Problem Solving Involving Subtraction.Worked ExampleThere are 1 244 male students in a college. If the number

female studentsis 327 less than the number of male students, how many

female students are there?Solution1. Understand the problem Given information:- Number of male students = 1 244 The number of female students is 327 less than the number of male students.2. Devise a plan Use subtraction.

3. Carry out the plan.     4. Check

    Use addition to check.

MULTIPLICATION OF WHOLE NUMBERS

1. Multiplication is a process of repeated addition.    

2.Changing the order of numbers in multiplication does

not affect the product. For example:- 6 × 3 = 18

3 × 6 = 18 3. The product of any number and 0 is 0. For example:- 10 × 0 = 0

0 × 10 = 04. A number multiplied by 1 is the number itself. For example:- 36 × 1 = 36

Worked example Find the product of  42 and 426.

Solution

1 6 8 8 08 4 4

B)Problem Solving involving MultiplicationWorked exampleMarion can sew 45 handkerchiefs in one day.How many can she sew in a week?Solution1.Understand the problem Given information:- Number of handkerchiefs sewn in one day = 45 Find: Total number of handkerchiefs sewn in a week.

2. Devise a plan Use multiplication.3.Carry out the plan 4. Check Multiply again to see if you gate the same

answer.

DIVISION OF WHOLE NUMBERS

A) DIVISION1. Division is equal gathering or equal sharing.

2.When a number is divided by 0, it cannot be defined.

For example:- 8 ÷ 0 cannot be defined.

3. When a number is divided by 1, the quotient is the number itself. For example:- 5 ÷ 1 = 54. When 0 is divided by any number, the quotient is 0. For example:- 0 ÷ 58 = 05. Changing the order of numbers in division will affect the answer. For example:-

Worked Example(a)Divide 1 694 by 14(b) Find the value 925 ÷ 4 

Solution

11

541

B) Problem Solving involving Division Worked Example160 table are arranged equally in 10 rows.How many table are there in each row?Solution 1. Understand the problem 160 table are arranged equally in 10 rows.2. Devise a plan Use division.3. Carry out the plan

4. Check Check by multiplication. 10 x 16 = 160

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