Final answer:
David can check his work by using alternative methods such as re-expressing the numbers, simplifying again, verifying with estimation, and confirming the proper use of significant figures.
Step-by-step explanation:
To check his work after evaluating the expression 125−7×10, David could use an alternative method such as re-expressing the numbers and simplifying again or using estimation. For example, recognizing that 24 is divisible by 8, he might re-express 125 as 24×1012. David would then perform 24×1012 − 7, which simplifies to 3 × 105. All these methods will lead to the same answer if done correctly. Checking for reasonableness and that the significant figures are used properly after using a calculator is also a good strategy. The importance of significant figures in mathematical operations cannot be overstated, and for expressions like 337/217, ensuring that the answer is limited to the correct number of significant figures is key to obtaining a precise result.