Home MATHEMATICS TOPIC 3: DECIMAL AND PERCENTAGE ~ MATHEMATICS FORM 1

TOPIC 3: DECIMAL AND PERCENTAGE ~ MATHEMATICS FORM 1

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BASIC MATHEMATICS FORM ONE FULL NOTES PERIMETERS AND AREAS COORDINATE OF A POINT PROFIT AND LOSS NUMBERS GEOMETRY Approximations UNITS DECIMAL AND PERCENTAGEFRACTIONS TOPIC 1: NUMBERS ~ MATHEMATICS FORM 1

TOPIC 3: DECIMAL AND PERCENTAGE

Explain the concept of decimals

A decimal- is defined as a number which consist of two parts separated by a point.The parts are whole number part and fractional part

Example 1

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Example 2

Https://sdimg.blob.core.windows.net/images/shuledirect/22472/original/decimal_Ex_1455529866329.png

Conversion of Fractions to Terminating Decimals and Vice Versa

Convert fractions to terminating decimals and vice versa

The first place after the decimal point is called tenths.The second place after the decimal point is called hundredths e.t.c

Consider the decimal number 8.152

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NOTE

To convert a fraction into decimal, divide the numerator by denominator

To convert a decimal into fraction, write the digits after the decimal point as tenths, or hundredths or thousandths depending on the number of decimal places.

Example 3

Convert the following fractions into decimals

Https://sdimg.blob.core.windows.net/images/shuledirect/22472/original/convert_1455530463349.png

Solution

Divide the numerator by denominator

Https://sdimg.blob.core.windows.net/images/shuledirect/22472/original/solv_1_1455531069219.png

Operations and Decimals

Addition of Decimals

Add decimals

Example 4

Evaluate

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Solution

Https://sdimg.blob.core.windows.net/images/shuledirect/22472/original/solution_1455531913543.png

Subtraction of Decimals

Subtract decimals

Example 5

Https://sdimg.blob.core.windows.net/images/shuledirect/22472/original/subtract_1455532407771.png

Solution

Https://sdimg.blob.core.windows.net/images/shuledirect/22472/original/solution_1455532594899.png

Multiplication of Decimals​​ 

Multiply decimals

Example 6

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Solution

Https://sdimg.blob.core.windows.net/images/shuledirect/22472/original/solution_1455533362877.png

Mixed Operations with Decimals

Perform mixed operations with decimals

Example 7

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Solution

Https://sdimg.blob.core.windows.net/images/shuledirect/22472/original/solution_1455533682132.png

Word Problems Involving Decimals

Solve word problems involving decimals

Example 8

If 58 out of 100 students in a school are boys, then write a decimal for the part of the school that consists of boys.

Solution

We can write a fraction and a decimal for the part of the school that consists of boys.

fraction

decimal

58/100

0.58

Percentages

Expressing a Quantity as a Percentage

Express a quantity as a percentage

The percentage of a quantity is found by converting the percentage to a fraction or decimal and then multiply it by the quantity.

Example 9

Https://sdimg.blob.core.windows.net/images/shuledirect/22472/original/find_1455539062106.png

NOTE:

The concept of percentage of a quantity can be used to solve the problems involving percentage increase and decrease as shown in the below examples:-

A Fractions into Percentage and Vice Versa

Convert a fraction into percentage and vice versa

To change a fraction or a decimal into a percentage, multiply it by 100%

Example 10

Convert the following fractions into percentages

Https://sdimg.blob.core.windows.net/images/shuledirect/22472/original/solution_1455539945554.png

A Decimal into Percentage and Vice Versa

Convert a decimal into percentage and vice versa

To change a percentage into a fraction or a decimal, divide it by 100%

Example 11

Convert the following percentages into decimals