Estimate each of the following products by rounding off each number upwards and the second number downwards :
`680xx164`

Answer

To estimate the product of 680 and 164 by rounding off the first number upwards and the second number downwards, we can follow these steps:

### Step 1: Round 680 upwards
- The number 680 is rounded upwards to the nearest hundred.
- Since the hundreds digit is 6, we add 1 to it, making it 7.
- All other digits become 0.
- Therefore, 680 rounded upwards is **700**.

### Step 2: Round 164 downwards
- The number 164 is rounded downwards to the nearest hundred.
- The hundreds digit is 1, and since we are rounding down, we keep it as 1.
- All other digits become 0.
- Therefore, 164 rounded downwards is **100**.

### Step 3: Calculate the estimated product
- Now, we multiply the rounded numbers:
\[ 700 \times 100 \]
- To perform this multiplication, we can simply multiply 7 by 1 and then add the two zeros from the rounded numbers.
- Thus,
\[ 700 \times 100 = 70000 \]

### Final Answer
The estimated product of 680 and 164 is **70,000**.

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