Using a Problem-Solving Model to Solve and Justify Solutions(TEKS.Math.7.1.B)
Texas 7th Grade Math · Learn by Concept
Help Questions
Texas 7th Grade Math › Using a Problem-Solving Model to Solve and Justify Solutions(TEKS.Math.7.1.B)
A fundraiser sold 350 bars at \$2 each toward a \$1500 goal.
What is the first step to determine how much more money is needed to reach the goal?
Multiply 350 by 2
Subtract 350 from 1500
Divide 1500 by 2
Add 350 and 1500
Explanation
First compute the amount raised in dollars: $350 \times 2 = 700$. Then compare to the goal by calculating $1500 - 700$. Subtracting 350 from 1500 mixes units (bars vs. dollars), and the other options do not set up the needed comparison.
A water tank holds 800 liters. It currently has 275 liters. A pump adds 12 liters per minute.
Which calculation best checks whether running the pump for 44 minutes will fill the tank?
$275 + 44$
$800 - 275 \div 12$
$275 + 12 \times 44$
$800 \times 44 - 12$
Explanation
To check reasonableness, model the final amount after 44 minutes: $275 + 12 \times 44$. If this is at least 800, the time is reasonable. The other options do not represent adding 12 liters each minute to the current amount.
A class trip has a bus that costs \$540 total and museum tickets that cost \$8 each for 36 students.
After finding the total ticket cost, what is the next step to find the total trip cost?
Subtract the ticket total from 540
Add the bus cost and the ticket total
Multiply 540 by 36
Divide 540 by 8
Explanation
The plan is to combine the fixed bus cost with the total ticket cost. After computing $36 \times 8$ for tickets, add that result to $540$ to get the total. Subtracting finds a difference, and multiplying or dividing misuses the quantities.
A recipe uses 3 cups of flour to make 24 cookies. You want to make 60 cookies.
What is the first step to determine how many cups of flour are needed?
Multiply 60 by 3
Add 60 and 24
Divide 24 by 60
Compute $60 \div 24$ to find the scale factor
Explanation
Start by finding how many times larger 60 cookies is compared to 24: $60 \div 24 = 2.5$. Then multiply $3 \times 2.5$ to get the flour needed. The other options use incorrect operations or reverse the ratio.
Mia has \$125 saved and earns \$9 for each lawn she mows. She wants at least \$250.
Which calculation would you use to check if mowing 14 lawns is enough to reach her goal?
$125 + 9 \times 14$
$250 - 14$
$125 \times 14$
$250 \div 9$
Explanation
Compute her total after 14 lawns: $125 + 9 \times 14$, then compare to 250. Subtracting 14 ignores earnings per lawn, and multiplying $125$ by $14$ or dividing $250$ by $9$ does not model the situation.