Adding + rational numbers - examples

  1. Diophantus
    diofantos_1 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
    coffe 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
    pave 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
    time Write time in minutes rounded to one decimal place: 5 h 28 m 26 s.
  5. Water
    tanks Mix 21 l of water with temperature of 38 °C, 67 l warm of 34 °C and 14 l water of 32 °C. What is the temperature of the mixed water immediately after mixing?
  6. Homework
    old_phone_1 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
    numbers2_4 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
  8. Addends
    1plus1 Number 839 divide into the two addends that the first was 17 greater than 60% of the second. Determine these addends.
  9. Fraction
    Gauss_stamp Fraction ? write as fraction a/b, a, b is integers numerator/denominator.
  10. Relay-race
    sprinters 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
    fractions_2 Write decimal number 8.638333333 as a fraction A/B in the basic form. Given decimal has infinite repeating figures.
  12. Wire
    wire_1 From wire 53 meters long they cut of 12.1 m and then 13.1 m. How many meters of wire left?
  13. Evaluate
    calculator_3 The division of numbers 18 and 6 increase by product of the numbers 156 and 0.001
  14. The Stolen Money
    magic2_1 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
    expr_1 Evaluate this expressions: a) 5[3 + 4(2.8 - 3)] b) 5×(8-4)÷4-2
  16. Simplify 3
    fractal_14 Simplify mixed numerals expression: 8 1/4- 3 2/5 - (2 1/3 - 1/4) Show your solution.

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