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# Feedback Q&A on Arithmetic

by Ron Kurtus

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

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

## List of most recent 10 letters

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

Fractions |
Adding two fractions | USA |

Numbers |
Sum of numbers | Fiji |

General |
Combine two expressions | Ghana |

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

General |
Filling a can with water | Ghana |

Fractions |
Sum as a frction | UK |

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

General |
Calculate distance | Mpumalanga |

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

General |
What is trigonometry? | India |

## Adding two fractions

Topic: **Fractions**

### Question

October 9, 2016

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.

## Sum of numbers

Topic: **Numbers**

### Question

March 2, 2016

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

## Combine two expressions

Topic: **General**

### Question

November 24, 2015

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.

## Convert 20 base 2 to base 10

Topic: **Numbers**

### Question

November 20, 2015

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.

## Filling a can with water

Topic: **General**

### Question

October 8, 2015

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.

## Sum as a frction

Topic: **Fractions**

### Question

May 7, 2015

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.

## Change 3/4 to ?/100

Topic: **Fractions**

### Question

September 21, 2012

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

## Calculate distance

Topic: **General**

### Question

September 15, 2012

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.

## Can you help me on my math lessons?

Topic: **General**

### Question

March 7, 2012

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.

## What is trigonometry?

Topic: **General**

### Question

February 8, 2012

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.

## Summary

Hopefully, this reader feedback has helped provide information about Arithmetic issues.

Always do your best

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## Feedback Q&A on Arithmetic