Decimals MCQ Test — Class 7 CBSE

Solution:

In the number 7.348, the digit '7' is in the units place.

The digit '3' is in the tenths place, meaning 3/10.

The digit '4' is in the hundredths place, meaning 4/100.

The digit '8' is in the thousandths place, meaning 8/1000.

Solution:

To convert 3/8 to a decimal, we perform the division 3 ÷ 8.

3 ÷ 8 = 0.375.

Rohan incorrectly assumed that the denominator '8' directly relates to the hundredths place '8' when it does not. The correct decimal representation is 0.375, not 0.38.

Solution:

To compare 0.6 and 0.55, it's helpful to make them have the same number of decimal places.

0.6 can be written as 0.60 (adding a zero at the end does not change its value).

Now, compare 0.60 and 0.55. Looking at the hundredths place, 60 is greater than 55.

Therefore, 0.6 is greater than 0.55.

Solution:

We know that 1 rupee = 100 paise.

Therefore, 75 paise can be written as 75/100 of a rupee.

As a decimal, 75/100 is 0.75.

Combining the rupees and paise, 7 rupees and 75 paise is 7 + 0.75 = ₹ 7.75.

Solution:

When adding decimal numbers, it is essential to align the decimal points vertically.

This ensures that digits with the same place value are added together (e.g., tenths with tenths, hundredths with hundredths, ones with ones).

If the decimal points are not aligned, you would be adding digits from different place values, leading to an incorrect sum.

While having the same number of digits after the decimal (by adding trailing zeros) can be helpful, it's not strictly 'crucial' like aligning the decimal point, which is non-negotiable for correct addition.

Solution:

To find the remaining rice, we need to subtract the sold amount from the initial amount: 15.5 kg - 7.25 kg.

Write 15.5 as 15.50 to have the same number of decimal places as 7.25.

Align the decimal points and subtract: 15.50 - 7.25

Subtracting column by column: (0-5 not possible, borrow from 5 to make it 10) 10-5=5; (4-2=2); (5-7 not possible, borrow from 1 to make it 15) 15-7=8. Result is 8.25.

Solution:

The number 100 has two zeros.

When multiplying a decimal by 100, the decimal point shifts two places to the right.

Starting with 3.4, moving the decimal point one place to the right gives 34.0.

Moving it another place to the right (by adding a zero) gives 340.0. So, 3.4 × 100 = 340.

Solution:

First, convert 5 mm to cm. Since 1 cm = 10 mm, 5 mm = 5/10 cm = 0.5 cm.

Now, the total length in cm is 4 cm + 0.5 cm = 4.5 cm.

Next, convert 4.5 cm to meters. Since 1 m = 100 cm, 1 cm = 1/100 m.

So, 4.5 cm = 4.5 / 100 m = 0.045 m.

Solution:

Let's rewrite all numbers with the same number of decimal places (two places, since 0.88 has two):

0.8 becomes 0.80

0.08 remains 0.08

0.88 remains 0.88

Now compare 0.80, 0.08, and 0.88. Thinking of them as 80, 8, and 88 after the decimal point, we can clearly see the order.

The ascending order is 0.08, 0.80 (which is 0.8), 0.88.

Solution:

First, calculate the total amount of apples used and sold: 2.35 kg (for juice) + 1.5 kg (sold).

Adding these amounts: 2.35 + 1.50 = 3.85 kg.

Now, subtract this total from the initial amount of apples: 5 kg - 3.85 kg.

Write 5 as 5.00 for subtraction: 5.00 - 3.85 = 1.15 kg.