# Adding + rational numbers - examples

1. Diophantus
We know little about this Greek mathematician from Alexandria, except that he lived around 3rd century A.D. Thanks to an admirer of his, who described his life by means of an algebraic riddle, we know at least something about his life. Diophantus's youth l
2. Coffee
In stock are three kinds of branded coffee prices: I. kind......248 Kč/kg II. kind......134 Kč/kg III. kind.....270 Kč/kg Mixing these three species in the ratio 10:7:7 create a mixture. What will be the price of 1100 grams of this mixture?
3. Store
One meter of the textile were discounted by 2 USD. Now 9 m of textile cost as before 8 m. Calculate the old and new price of 1 m of the textile.
4. Time
Write time in minutes rounded to one decimal place: 5 h 28 m 26 s.
5. Water
Mix 68 l of water with temperature of 87 °C, 17 l warm of 42 °C and 55 l water of 50 °C. What is the temperature of the mixed water immediately after mixing?
6. Homework
The monthly fee for the phone is 12 USD and for phone unit 0.08 USD. How much family pay phone in the first quarter Q1, if on January 1 had on the counter 97362 units and on April 1 97946 units.
7. David number
Jana and David train the addition of the decimal numbers so that each of them will write a single number and these two numbers then add up. The last example was 11.11. David's number had the same number of digits before the decimal point, the Jane's number
Number 839 divide into the two addends that the first was 17 greater than 60% of the second. Determine these addends.
9. Fraction
Fraction ? write as fraction a/b, a, b is integers numerator/denominator.
10. Relay-race
Kate ran 170 meters at 29.8 seconds, Suzan at 29.3 seconds, Roza at 34 seconds and Žofka at 30.4 seconds. How long took to run 4x170 m relay-race?
11. Decimal to fraction
Write decimal number 8.638333333 as a fraction A/B in the basic form. Given decimal has infinite repeating figures.
12. Wire
From wire 53 meters long they cut of 12.1 m and then 13.1 m. How many meters of wire left?
13. Evaluate
The division of numbers 18 and 6 increase by product of the numbers 156 and 0.001
14. The Stolen Money
A man walks into a store and steals a \$100 bill. 5 minutes later, he returns to the store and buys stuff worth \$70. He pays with the bill that he had stolen, so the owner of the store returns him \$30. How many dollars did the store owner lose?
15. Expression 8
Evaluate this expressions: a) 5[3 + 4(2.8 - 3)] b) 5×(8-4)÷4-2
16. Simplify 3
Simplify mixed numerals expression: 8 1/4- 3 2/5 - (2 1/3 - 1/4) Show your solution.
17. The temperature
The temperature at 1:00 was 10 F. Between 1:00 and 2:00, the temperature dropped 15F. Between 2:00 and 3:00, the temperature rose 3F. What is the temperature at 3:00?

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