# 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.

## List of most recent 10 letters

### Country

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

Next 10

Topic: Fractions

### Question

October 9, 2016

what is 2/5 + 1/2

Gane - USA

27355

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.

## 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

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

26561

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.

## Convert 20 base 2 to base 10

Topic: Numbers

### Question

November 20, 2015

Convert 20 base 2 to base 10

Oyetunde - Nigeria

26551

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?

26426

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

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

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

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

22489

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

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.

Next 10

## Resources and references

The following are some resources on this topic.

### Websites

Arithmetic Resources

### Books

Top-rated books on Arithmetic

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