Answer :
Answer:
Explanation:
If Rohan wants to add two numbers but doesn't remember the block he should use, he can use a few different methods depending on the situation:
1. **Using Paper and Pen:**
Rohan can write down the two numbers vertically, aligning the digits according to their place value (ones, tens, hundreds, etc.). Then, starting from the rightmost digit, he can add each column separately, carrying over any extra digits to the next column if needed.
2. **Using a Calculator:**
If Rohan has access to a calculator, he can simply input the two numbers and press the "+" button to get the sum. Calculators are designed to perform arithmetic operations quickly and accurately.
3. **Using Mental Math:**
If the numbers are small enough, Rohan can add them mentally. For example, for two-digit numbers, he can add the digits in the ones place first, then add the digits in the tens place, carrying over if necessary.
If Rohan needs further assistance or clarification on any of these methods, he can ask someone for help or refer to instructional materials on addition.