Subtract 21139 from 92018 and round off the resultant to the nearest tens?

Options

A. 70870
B. 70879
C. 70800
D. 70880

Answer

To solve the problem of subtracting 21139 from 92018 and rounding off the result to the nearest tens, we can follow these steps:

### Step 1: Set up the subtraction
We need to subtract 21139 from 92018. We can write it as:

```
92018
- 21139
```

### Step 2: Perform the subtraction
We will subtract each digit starting from the rightmost side (the units place):

- **Units place**: 8 - 9 cannot be done without borrowing. So, we borrow from the next digit (1 becomes 0, and 8 becomes 18).
- 18 - 9 = 9
- **Tens place**: Now we have 0 (after borrowing) - 3. We need to borrow again from the next digit (2 becomes 1, and 0 becomes 10).
- 10 - 3 = 7
- **Hundreds place**: Now we have 1 (after borrowing) - 1 = 0.
- **Thousands place**: 0 - 1 cannot be done, so we borrow from the next digit (9 becomes 8, and 0 becomes 10).
- 10 - 1 = 9
- **Ten-thousands place**: 8 - 2 = 6.

Putting it all together, we get:

```
92018
- 21139
-------
70879
```

### Step 3: Round off to the nearest tens
Now we have the result of the subtraction, which is 70879. We need to round this number to the nearest tens.

- The last digit (units place) is 9.
- According to rounding rules, if the last digit is 5 or more, we round up. Since 9 is greater than 5, we round up.

Thus, we round 70879 to 70880.

### Final Answer
The final answer, after rounding off to the nearest tens, is **70880**.

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