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Mathematics Form 1 - Unit 1 Rational Number

1.1

 Integers

 

 

Definition

 

 

 

 

 

Positive and negative whole numbers including 00.

 

 

Positive numbers:

 

  • Numbers written with the '++' sign or without any sign.

  • Examples: +12,4,+7,1+12,4,+7,1

  • Positive integers are integers that have a value greater than 00.

 

Negative numbers:

 

  • Numbers written with the '−−' sign.

  • Examples: −6,−2,−15,−27−6,−2,−15,−27

  • Negative integers are integers that are lower than 00.

 

 

Example

 

 

 

 

 

Determine whether the following numbers is an integer.

(i) 7227​

(ii) 6.86.8

(iii) −12−12

 

 

 

 

 

(i) 7227​ is not an integer because it is a fraction.

(ii) 6.86.8 is not an integer because it is a decimal.

(iii) −12−12 is an integer.

 

 

Integers on a number line:

 

  • On a number line, the numbers in the positive direction are always greater than the numbers in the negative direction.

 

Integers in order:

 

1.3

 Positive and Negative Fractions

 

  • Positive fractions are fractions more than 00.

  • Negative fractions are fractions less than 00.

 

 

  • The values of two or more fractions can be compared by equating the denominator first.

  • Then, arrange the fractions in ascending or descending order.

 

Combined basic arithmetic operations of positive and negative fractions:

 


 

Example

 

 

 

 

 

Solve:

 116×(34−15)=76×(15−420)=76×1120=77120.​ 161​×(43​−51​)=67​×(2015−4​)=67​×2011​=12077​.​

1.4

 Positive and Negative Decimals

 

  • Positive decimals are decimals more than 00.

  • Negative decimals are decimals less than 00.

 

 

  • The values of two or more decimals can be compared and arranged in ascending order or descending order.

 

Combined basic arithmetic operations of positive and negative decimals:

 

 

Example

 

 

 

 

 

Calculate:

(i)

 (9.37−0.63)×(−0.4)=8.74×(−0.4)=−3.496.​ (9.37−0.63)×(−0.4)=8.74×(−0.4)=−3.496.​

(ii)

 2.34+3.1÷0.2=2.34+(3.1÷0.2)=2.34+15.5=17.84.​ 2.34+3.1÷0.2=2.34+(3.1÷0.2)=2.34+15.5=17.84.​


Rational Numbers

1.5

 Rational Numbers

 

 

Definition

 

 

 

 

 

A number that can be written in fractional form pqqp, where pp and qq are integers and q≠0q​=0.

 

 

  • Examples: −12,7.5,4−21​,7.5,4

 

Combined basic arithmetic operations of rational numbers:

 


 

Example

 

 

 

 

 

Calculate:

 −0.8+34×(−216)=−810+34×(−136)=−810+(−138)=−6480−13080=−19480=−21740.​ −0.8+43​×(−261​)=−108​+43​×(−613​)=−108​+(−813​)=−8064​−80130​=−80194​=−24017​.​

TF

Mathematics Form 1 - Unit 1 Rational Number

1.1

 Integers

 

 

Definition

 

 

 

 

 

Positive and negative whole numbers including 00.

 

 

Positive numbers:

 

  • Numbers written with the '++' sign or without any sign.

  • Examples: +12,4,+7,1+12,4,+7,1

  • Positive integers are integers that have a value greater than 00.

 

Negative numbers:

 

  • Numbers written with the '−−' sign.

  • Examples: −6,−2,−15,−27−6,−2,−15,−27

  • Negative integers are integers that are lower than 00.

 

 

Example

 

 

 

 

 

Determine whether the following numbers is an integer.

(i) 7227​

(ii) 6.86.8

(iii) −12−12

 

 

 

 

 

(i) 7227​ is not an integer because it is a fraction.

(ii) 6.86.8 is not an integer because it is a decimal.

(iii) −12−12 is an integer.

 

 

Integers on a number line:

 

  • On a number line, the numbers in the positive direction are always greater than the numbers in the negative direction.

 

Integers in order:

 

1.3

 Positive and Negative Fractions

 

  • Positive fractions are fractions more than 00.

  • Negative fractions are fractions less than 00.

 

 

  • The values of two or more fractions can be compared by equating the denominator first.

  • Then, arrange the fractions in ascending or descending order.

 

Combined basic arithmetic operations of positive and negative fractions:

 


 

Example

 

 

 

 

 

Solve:

 116×(34−15)=76×(15−420)=76×1120=77120.​ 161​×(43​−51​)=67​×(2015−4​)=67​×2011​=12077​.​

1.4

 Positive and Negative Decimals

 

  • Positive decimals are decimals more than 00.

  • Negative decimals are decimals less than 00.

 

 

  • The values of two or more decimals can be compared and arranged in ascending order or descending order.

 

Combined basic arithmetic operations of positive and negative decimals:

 

 

Example

 

 

 

 

 

Calculate:

(i)

 (9.37−0.63)×(−0.4)=8.74×(−0.4)=−3.496.​ (9.37−0.63)×(−0.4)=8.74×(−0.4)=−3.496.​

(ii)

 2.34+3.1÷0.2=2.34+(3.1÷0.2)=2.34+15.5=17.84.​ 2.34+3.1÷0.2=2.34+(3.1÷0.2)=2.34+15.5=17.84.​


Rational Numbers

1.5

 Rational Numbers

 

 

Definition

 

 

 

 

 

A number that can be written in fractional form pqqp, where pp and qq are integers and q≠0q​=0.

 

 

  • Examples: −12,7.5,4−21​,7.5,4

 

Combined basic arithmetic operations of rational numbers:

 


 

Example

 

 

 

 

 

Calculate:

 −0.8+34×(−216)=−810+34×(−136)=−810+(−138)=−6480−13080=−19480=−21740.​ −0.8+43​×(−261​)=−108​+43​×(−613​)=−108​+(−813​)=−8064​−80130​=−80194​=−24017​.​

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