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Q1. Express
−35 as a rational number with denominator: (i) 20 (ii) −40
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Q2. Arrange the following numbers in ascending
order: 4 /− 9 , − 5 /12 ; 7/ − 18 ; −
2/ 3
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Q3. Arrange the following numbers in descending
order: − 5, 6/ ; − 7/ 12 ; − 13/ 28 ;
23/ − 24
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Q4. Represent −25/6 on the number line.
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Q5. Represent 42/3on the number line.
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Q6. What number should be added to −78to get 49?
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Q7. The sum of two rational numbers is −12. If one
of the numbers is 56, find the other.
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Q8. What number should be subtracted from −23 to
get −12?
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Q9. Subtract: −3213 from −65
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Q10. Find the following products: (i) 16−21×145
(ii) 724×−48
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Q11. Verify whether the given statement is true or
not: (i) <59÷13) ÷ 52= 59÷(13÷52)
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Q12. Divide the sum of 135and−127by the product of
−317and1−2.
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Q13. The product of two rational numbers is −169.
If one of the numbers is −43, find the other.
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Q14. Find three rational numbers between 4and5.
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Q15. Find three rational numbers between 23and34.
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Q16. A drum full of rice weights 4016kg. If the
empty drum weights 1334kg, find the weight of rice in the drum.
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Q17. A car is moving at an average speed of
4025km/h. How much distance will it cover in 712h?
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Q18. Raju
earns Rs16000/m. He spends 14of his income on food; 310of the
remainder on house rent and 521of the remainder on education of children. How
much money is still left with him?
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Q19. After reading 79of a book, 40pages are left.
How many pages are there in the book?
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Q20. Are these pairs forming pair of equivalent
rational numbers? (i) 1435and2145 (ii) −1226and1839
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Class 09 Atoms and Molecules Numerical Problem based on Law of chemical Combination Law of conservation of mass Law of constant proportion Empirical formula 1. If 10 grams of CaCO 3 on heating gave 4.4g of CO 2 and 5.6g of CaO, show that these observations are in agreement with the law of conservation of mass.(Based on Law of conservation of mass) Solution: Mass of the reactants = 10g ; Mass of the products = 4.4 + 6.6g = 10g Since the mass of the reactants is equal to the mass of the products, the observations are in agreement with the law of conservation of mass. 2. 1.375 g of cupric oxide was reduced by heating and the weight of copper that remained was 1.098g. In another experiment 1.179 g of copper was dissolved in nitric acid and the resulting copper nitrate was converted into cupric oxide by ignition . The weight of cupric oxide formed was 1.476 g. which law of chemical combinations does this data state? Solution: in first experiment: Copper oxide = 1....
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