Operations on rational numbers & decimals Quiz - ICSE Class 7 Mathematics

Free practice quiz: Operations on rational numbers & decimals (ICSE Class 7 Mathematics). 51 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

Sample questions

1. What is the value of $(-3.5) \times (-2) + 1.5$?

   1. 8.5
   2. 7.5
   3. 6.5
   4. 5.5
   Show answer

   Answer: A. 8.5

   First, multiply $-3.5$ by $-2$. The product of two negative numbers is positive. So, $(-3.5) \times (-2) = 7.0$. Then, add $1.5$ to $7.0$. $7.0 + 1.5 = 8.5$. Therefore, the value is $8.5$.

2. If $x = -1.5$ and $y = 2.5$, what is $x \times y$?

   1. $-3.75$
   2. $3.75$
   3. $-2.75$
   4. $2.75$
   Show answer

   Answer: A. $-3.75$

   Multiply the numbers as if they were positive: $1.5 \times 2.5$. $15 \times 25 = 375$. Since one number is negative and the other is positive, their product will be negative. There is one decimal place in $1.5$ and one in $2.5$, so there will be two decimal places in the product. Thus, $x \times y = -3.75$.

3. What is the sum of $\frac{1}{3}$ and $\frac{2}{5}$?

   1. $\frac{3}{8}$
   2. $\frac{11}{15}$
   3. $\frac{7}{15}$
   4. $\frac{1}{2}$
   Show answer

   Answer: B. $\frac{11}{15}$

   To add fractions, find a common denominator. The least common multiple of 3 and 5 is 15. Rewrite $\frac{1}{3}$ as $\frac{1 \times 5}{3 \times 5} = \frac{5}{15}$. Rewrite $\frac{2}{5}$ as $\frac{2 \times 3}{5 \times 3} = \frac{6}{15}$. Now, add the fractions: $\frac{5}{15} + \frac{6}{15} = \frac{5+6}{15} = \frac{11}{15}$.

4. Calculate the product of $-0.5$ and $-2.5$.

   1. 1.25
   2. -1.25
   3. 0.125
   4. -0.125
   Show answer

   Answer: A. 1.25

   When multiplying two negative numbers, the result is positive. Multiply $0.5$ by $2.5$. $5 \times 25 = 125$. Since there is one decimal place in $0.5$ and one in $2.5$, the product has $1+1=2$ decimal places. So, the product is $1.25$.

5. If $x = -1.2$ and $y = -0.3$, what is $x \times y$?

   1. 0.36
   2. -0.36
   3. 3.6
   4. -3.6
   Show answer

   Answer: A. 0.36

   When multiplying two negative numbers, the result is positive. Multiply $1.2$ by $0.3$. $12 \times 3 = 36$. Since there is one decimal place in $1.2$ and one in $0.3$, the product will have $1+1=2$ decimal places. So, the product is $0.36$.

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