Using Estimation
Fruit Prices
| Fruit | Cost (per pound) |
|---|---|
| apples | $1.89 |
| cherries | $5.28 |
| grapes | $2.78 |
Karla is making fresh grape jelly. She buys 18.7 pounds of grapes.
Estimate the total cost.
$2.78(18.7)
Karla will spend about $\square$ on grapes.
Answer (2)
To estimate Karla's total cost for grapes, we round the cost per pound from $2.78 to $3 and the number of pounds from 18.7 to 19. Multiplying these rounded values gives us an estimated total cost of $57.
;
Round the price per pound of grapes: $2.78 \approx $3.
Round the number of pounds of grapes: 18.7 pounds \approx 19 pounds.
Multiply the rounded values to estimate the total cost: 3 × 19 = 57 .
Karla will spend about $57 on grapes.
Explanation
Understanding the Problem Let's break down how to estimate the total cost of the grapes Karla bought!
Rounding the Price First, we need to round the price per pound of grapes and the number of pounds Karla bought to make the calculation easier. The price per pound is $2.78, which we can round to $3.
Rounding the Quantity Next, we round the number of pounds Karla bought, which is 18.7 pounds. We can round this to 19 pounds.
Calculating the Estimated Cost Now, we multiply the rounded price per pound by the rounded number of pounds to estimate the total cost: 3 × 19 = 57
Final Answer So, Karla will spend about $\boxed{57} on grapes.
Examples
Estimating costs is very useful in everyday life. For example, when you go grocery shopping, you can quickly estimate the total cost of your items to make sure you stay within your budget. If you're buying 8 items that cost around $2.50 each, you can estimate the total cost by rounding $2.50 to $3 and multiplying by 8, which gives you $24. This helps you avoid surprises at the checkout!
