Which subtraction model-take-away, missing addend, comparison, or measurement-corresponds best to each problem below? (a) Ted solved 17 problems and John solved 15 problems. How many more problems has Ted solved than John? (b) Steve has saved \( \$ 50 \) toward the \( \$ 60 \) CD player he wants to buy. How much money does he have to add to his savings to purchase the player? (a) Which subtraction model corresponds best to this problem? Measurement Comparison

In both cases, you're looking at how to relate quantities and determine differences! For (a), Ted’s accomplishment is being compared to John's, making it a classic comparison model. The essence of the problem centers around figuring out how much more one quantity surpasses another. For (b), Steve’s savings situation illustrates the missing addend model. Here, it's all about finding out how much more he needs to reach his goal of \( \$ 60 \). He knows how much he has and needs to calculate the missing piece to find the total amount required for his desired purchase!