Question

Ted is saving for a toy. He has no money now, but

he figures that if he saves $D per week for the next
4 weeks he will have $1 more than he needs for the
toy. Write an expression for the cost of the toy Ted
wants to buy in terms of D. Explain.

Answer 1

4D - 1

Explanation:

So, if Ted saves $D for 4 weeks, then this amount will be equal to 4D because multiplication is simply repeated addition. We can imagine this situation as D+D+D+D, for the 4 weeks he is saving. We can simplify this to 4D in the expression.

Next, the question tells us that this will be 1 dollar more than needed. So, if we want to find the cost, we need to subtract that dollar.

Thus, the final expression is 4D - 1 because this represents 1 dollar less than the money he saves for 4 weeks.