Question 2 Select all the sums that a mental strategy should be used to solve. \( 598+312 \)

To determine whether the sum \( 598 + 312 \) is suitable for mental calculation, let's explore effective mental strategies to solve it. ### Strategy 1: **Rounding and Adjusting** 1. **Round One Number Up**: Round 598 up to 600. 2. **Add the Rounded Number to the Other Number**: \[ 600 + 312 = 912 \] 3. **Adjust for the Rounding**: Since you added 2 to 598 to make it 600, subtract that 2 from the total. \[ 912 - 2 = 910 \] 4. **Final Answer**: \( 598 + 312 = 910 \) ### Strategy 2: **Breaking Down into Place Values** 1. **Separate Each Number by Place Value**: \[ 598 = 500 + 90 + 8 \] \[ 312 = 300 + 10 + 2 \] 2. **Add Corresponding Place Values**: \[ 500 + 300 = 800 \] \[ 90 + 10 = 100 \] \[ 8 + 2 = 10 \] 3. **Combine the Sums**: \[ 800 + 100 + 10 = 910 \] 4. **Final Answer**: \( 598 + 312 = 910 \) ### Strategy 3: **Standard Addition with Carryover** 1. **Add the Ones Place**: \[ 8 + 2 = 10 \quad (\text{Write down 0 and carry over 1}) \] 2. **Add the Tens Place Including Carryover**: \[ 9 + 1 + 1 = 11 \quad (\text{Write down 1 and carry over 1}) \] 3. **Add the Hundreds Place Including Carryover**: \[ 5 + 3 + 1 = 9 \] 4. **Combine the Results**: \[ 900 + 10 = 910 \] 5. **Final Answer**: \( 598 + 312 = 910 \) ### Conclusion Yes, \( 598 + 312 \) is a sum that can be effectively solved using mental strategies. By employing techniques such as rounding and adjusting, breaking down into place values, or performing standard addition with carryover, you can arrive at the correct answer of **910** without the need for written calculations.