Decimals class 5 interactive worksheet - Free Printable

Let's solve the problems step by step.

---

Problem 1: Form the greatest number less than 1 using digits 5, 8, and 9 only once.

To form the greatest number less than 1 using the digits 5, 8, and 9, we need to place the largest digit in the tenths place, the next largest in the hundredths place, and the smallest in the thousandths place. The number should be a decimal less than 1, so it will start with 0.

The digits are 5, 8, and 9. Arranging them in descending order gives us:
- Tenths place: 9
- Hundredths place: 8
- Thousandths place: 5

Thus, the greatest number less than 1 is:
\[
0.985
\]

Answer:
\[
\boxed{0.985}
\]

---

Problem 2: \(0.723 \times 1000 = \) ______

When multiplying a decimal by 1000, we move the decimal point three places to the right:
\[
0.723 \times 1000 = 723
\]

Answer:
\[
\boxed{723}
\]

---

Problem 3: Complete the given series.

#### (i) \(2.7, 3.2, 3.7, \_\_\_\_, \_\_\_\_ \)

This is an arithmetic sequence where each term increases by a constant difference. Let's find the common difference:
\[
3.2 - 2.7 = 0.5
\]
\[
3.7 - 3.2 = 0.5
\]

The common difference is \(0.5\). Adding \(0.5\) to the last term \(3.7\):
\[
3.7 + 0.5 = 4.2
\]
\[
4.2 + 0.5 = 4.7
\]

Thus, the completed series is:
\[
2.7, 3.2, 3.7, 4.2, 4.7
\]

Answer:
\[
\boxed{4.2, 4.7}
\]

#### (ii) \(5.73, 6.74, 7.75, \_\_\_\_, \_\_\_\_ \)

This is also an arithmetic sequence. Let's find the common difference:
\[
6.74 - 5.73 = 1.01
\]
\[
7.75 - 6.74 = 1.01
\]

The common difference is \(1.01\). Adding \(1.01\) to the last term \(7.75\):
\[
7.75 + 1.01 = 8.76
\]
\[
8.76 + 1.01 = 9.77
\]

Thus, the completed series is:
\[
5.73, 6.74, 7.75, 8.76, 9.77
\]

Answer:
\[
\boxed{8.76, 9.77}
\]

#### (iii) \(89.051, 189.061, 289.071, \_\_\_\_, \_\_\_\_ \)

This is an arithmetic sequence. Let's find the common difference:
\[
189.061 - 89.051 = 100.01
\]
\[
289.071 - 189.061 = 100.01
\]

The common difference is \(100.01\). Adding \(100.01\) to the last term \(289.071\):
\[
289.071 + 100.01 = 389.081
\]
\[
389.081 + 100.01 = 489.091
\]

Thus, the completed series is:
\[
89.051, 189.061, 289.071, 389.081, 489.091
\]

Answer:
\[
\boxed{389.081, 489.091}
\]

---

Problem 4: Find the number:

#### (i) 6 tenths more than 7.245

6 tenths is \(0.6\). Adding \(0.6\) to \(7.245\):
\[
7.245 + 0.6 = 7.845
\]

Answer:
\[
\boxed{7.845}
\]

#### (ii) 6 thousandths added to 18.023

6 thousandths is \(0.006\). Adding \(0.006\) to \(18.023\):
\[
18.023 + 0.006 = 18.029
\]

Answer:
\[
\boxed{18.029}
\]

#### (iii) 8 tenths and 4 hundredths less than 7

8 tenths is \(0.8\), and 4 hundredths is \(0.04\). Together, they are:
\[
0.8 + 0.04 = 0.84
\]

Subtracting \(0.84\) from \(7\):
\[
7 - 0.84 = 6.16
\]

Answer:
\[
\boxed{6.16}
\]

#### (iv) 1 tenth and 5 thousandths more than 9

1 tenth is \(0.1\), and 5 thousandths is \(0.005\). Together, they are:
\[
0.1 + 0.005 = 0.105
\]

Adding \(0.105\) to \(9\):
\[
9 + 0.105 = 9.105
\]

Answer:
\[
\boxed{9.105}
\]

---

Problem 5: Choose the right answer and fill in the blank.

#### (i) \(478.65 \div \_\_\_\_ = 47.865\)

We need to find the divisor. Let the divisor be \(x\). Then:
\[
478.65 \div x = 47.865
\]

Rearranging to solve for \(x\):
\[
x = \frac{478.65}{47.865}
\]

Perform the division:
\[
x = 10
\]

Thus, the correct answer is:
\[
\boxed{10}
\]

#### (ii) \(137.85 \times 10 = \_\_\_\_

Multiplying a number by 10 moves the decimal point one place to the right:
\[
137.85 \times 10 = 1378.5
\]

Thus, the correct answer is:
\[
\boxed{1378.5}
\]

---

Final Answers:

1. \(\boxed{0.985}\)
2. \(\boxed{723}\)
3. (i) \(\boxed{4.2, 4.7}\)
(ii) \(\boxed{8.76, 9.77}\)
(iii) \(\boxed{389.081, 489.091}\)
4. (i) \(\boxed{7.845}\)
(ii) \(\boxed{18.029}\)
(iii) \(\boxed{6.16}\)
(iv) \(\boxed{9.105}\)
5. (i) \(\boxed{10}\)
(ii) \(\boxed{1378.5}\)