Question

problem 25
marcus buys supplies costing $3.50, $2.25, and $4.99. what is the total cost?

problem 26
a piece of string is 12.4 meters long. if 5.8 meters is cut off, how much string remains?

problem 27
calculate: 4.2 × 3.5

problem 28
calculate: 0.7 × 0.6

problem 29
calculate: 24.8 ÷ 4

Explanation:

Problem 25

Step1: Add the three costs

To find the total cost, we add the three amounts: \( 3.50 + 2.25 + 4.99 \)
First, add \( 3.50 \) and \( 2.25 \): \( 3.50 + 2.25 = 5.75 \)
Then, add the result to \( 4.99 \): \( 5.75 + 4.99 = 10.74 \)

Step1: Subtract the cut - off length from the original length

To find the remaining length of the string, we subtract the length that is cut off from the original length. The original length is \( 12.4 \) meters and the length cut off is \( 5.8 \) meters. So we calculate \( 12.4−5.8 \)
\( 12.4 - 5.8=6.6 \)

Step1: Multiply the two decimals

To calculate \( 4.2\times3.5 \), we can think of it as multiplying \( 42\times35 \) and then adjusting the decimal places.
First, \( 42\times35 = 1470 \)
Since \( 4.2 \) has one decimal place and \( 3.5 \) has one decimal place, the product should have \( 1 + 1=2 \) decimal places.
So \( 4.2\times3.5=\frac{42}{10}\times\frac{35}{10}=\frac{42\times35}{100}=\frac{1470}{100} = 14.7 \)

Answer:

The total cost is \$10.74.

Problem 26