# Arithmetic Feedback

by Ron Kurtus

Readers have sent in a total of **19** comments and questions on Arithmetic issues. They are listed according to date.

You can read them to further your understanding of the subject.

## List of most recent 15 letters

## Title |
## Topic |
## Country |

Adding two fractions |
Fractions |
USA |

Sum of numbers |
Numbers |
Fiji |

Combine two expressions |
General |
Ghana |

Convert 20 base 2 to base 10 |
Numbers |
Nigeria |

Filling a can with water |
General |
Ghana |

Sum as a frction |
Fractions |
UK |

Change 3/4 to ?/100 |
Fractions |
South Africa |

Calculate distance |
General |
Mpumalanga |

Can you help me on my math lessons? |
General |
Canada |

What is trigonometry? |
General |
India |

What is arithmetic? |
General |
India |

Fraction has multiple instead of addition |
Fractions |
South Africa |

I have problems in math |
General |
USA |

Algebra problem with trains |
General |
India |

Is zero a negative number or positive number? |
General |
USA |

### Fractions

## Adding two fractions

October 9, 2016

### Question

what is 2/5 + 1/2

Gane - **USA** (27355)

### Answer

To add 2/5 + 1/2, you find the lowest common denominator, which would be 5 x 2 = 10.

Then change each fraction to have the same denominator: 2/5 = 2*2/5*2 = 4/10 and 1*5/2*5 = 5/10.

Finally: 4/10 + 5/10 = 9/10.

Follow a similar routine for adding other fractions.

### Numbers

## Sum of numbers

March 2, 2016

### Question

sum of the measured value;756, 37.2, 0.83, and 2.5

laisenia - **Fiji** (26834)

### Answer

This is an Arithmetic problem that you can do with a calculator or by hand. Put all as decimal numbers and add:

756.00

37.20

0.83

+ 2.50

-------

796.53

### General

## Combine two expressions

November 24, 2015

### Question

Evaluate (2x - y)*2 + ( 4x -3y)*2 where * is an exponent oor power

Adu - **Ghana** (26561)

### Answer

Note that ^ is usually used to denote raising to a power

(2x - y)^2 = (2x - y)(2x - y) = 4x^2 - 4xy + y^2

(4x - 3y)^2 = (4x - 3y)(4x - 3y) = 16x^2 - 24xy + 9y^2

You can then add like terms.

See Multiplying Binomial Expressions in the Algebra section for more information.

### Numbers

## Convert 20 base 2 to base 10

November 20, 2015

### Question

Convert 20 base 2 to base 10

Oyetunde - **Nigeria** (26551)

### Answer

The base 2 only uses the digits 0 and 1, so 20 is not possible. However, you can convert 20 base 10 to base 2 as: 10100.

You can use a conversion calculator to check this as well as to try other numbers.

### General

## Filling a can with water

October 8, 2015

### Question

A jerry-can is 2/5 full of water. if 15 litres is added to fill it up, how many litres can the tank hold?

Adu - **Ghana** (26426)

### Answer

This is actually an Algebra problem.

If X is the full amount, and the can is 2/5 full, then the empty part is 3/5.

So (3/5)X = 15 litres. Thus, 3X = 75 and X = 25 litres.

### Fractions

## Sum as a frction

May 7, 2015

### Question

3/7 + 5/7 as a fraction?

Tony - **UK** (25978)

### Answer

Since the bottom numbers (denominators) are the same, you simply add the top numbers (numerators): 3/7 = 5/7 = 8/7.

However, 8/7 is an improper fraction and should be reduced to 1 1/7.

### Fractions

## Change 3/4 to ?/100

September 21, 2012

### Question

Fraction 3/4=?/100

leola - **South Africa** (22934)

### Answer

Since 4 times 25 = 100, multiply 3/4 times 25/25 = 3*25/4*25 = 75/100

### General

## Calculate distance

September 15, 2012

### Question

How do u calculate distance ?

Thulane - **Mpumalanga** (22900)

### Answer

To calculate the distance, you need to compare with some source. it depends much on what you are trying to do.

### General

## Can you help me on my math lessons?

March 7, 2012

### Question

hi can you help me on my math lessons. i would apreasheat that im in grade 6

aya - **Canada** (22489)

### Answer

Take a look at my Arithmetic and Algebra sections. The lessons and mini-quizzes may help with your understanding.

I can answer some specific questions, but can't really give personal help.

Best wishes in doing well in math.

### General

## What is trigonometry?

February 8, 2012

### Question

what is meant by tignometry

sai - **India** (22415)

### Answer

Trigonometry is a mathematics subject related to geometry. Its primary use is a clever method to measure the size of a large object by comparing distances with a right triangle.

### General

## What is arithmetic?

October 15, 2011

### Question

What is exactly arithmetic?

Priyam - **India** (22078)

### Answer

Arithmetic is working with numbers, such as counting, adding, subtracting, multiplying and dividing. Dividing breaks numbers into fractions and decimals, which are a sub-set of arithmetic.

### Fractions

## Fraction has multiple instead of addition

September 3, 2011

### Question

What if a fraction has a multiple in the middle instead of an addition

Lwandisa - **South Africa** (21943)

### Answer

See Multiplying Fractions to see how to do it.

### General

## I have problems in math

February 1, 2011

### Question

ihave broublems in math so how to be good in this ?

please give me good idias please.

jouliet - **USA** (21125)

### Answer

Take a look at our sections on Arithmetic and Algebra to help you learn the subjects.

### General

## Algebra problem with trains

October 2, 2010

### Question

Two trains of 100 m each in length running in opposite directions cross each other in 6 seconds. If the speed of one train is 48km/hr, find the speed of another train.

Rupesh - **India** (20476)

### Answer

That is a good Algebra problem, not an Arithmetic problem. I think some data is missing.

Sorry we do not have the solution.

### General

## Is zero a negative number or positive number?

June 3, 2010

### Question

hello sir, good morning,

my name is irfan i am the student of class 6.

please help me and give me answer.

zero is the negative number or positive? why all the things becomes zero when multiplied with zero?

irfan - **USA** (19831)

### Answer

For a long time zero was not even considered a number, because it represents nothing. Zero is the turning point between positive and negative numbers, so it is neither positive or negative.

Positive is defined as greater than zero and negative is defined as less than zero.

Multiplying by nothing results in nothing. Thus multiplying by zero results in zero.

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