The student council runs a fundraiser. Writing and solving equations โ and an inequality for the goal โ keeps the plan on track.
The council's goal is $200. So far they have raised $45. President Aria translated the words into an equation: 45 + x = 200, where x is the amount still needed.
Subtract 45 from both sides: x = 200 โ 45 = $155 still needed. Check: 45 + 155 = 200. โ
Why is writing the equation before solving helpful here?
They raised $60 toward a $250 goal. Write 60 + x = 250 and solve for x.
Tickets sell for $8 each. The council needs $96 from ticket sales. Equation: 8x = 96, where x is the number of tickets.
Divide both sides by 8: x = 96 รท 8 = 12 tickets. Check: 8 ร 12 = 96. โ
Bracelets sell for $5 each, and they need $75. Solve 5x = 75 for the number of bracelets.
"We don't just want exactly $200 โ we want at least $200," Aria said. That is an inequality: x โฅ 200. Any amount of 200 or more is a success.
x โฅ 200 means x can be 200, 201, 250, โฆ The smallest whole-dollar amount that meets the goal is $200. Values like $180 do not satisfy it.
Why use x โฅ 200 instead of x = 200?
A prize needs at least 30 cans (c โฅ 30). What is the smallest whole number of cans that wins the prize?
For the snack stand, the council wrote 5x = 60 (x = number of combo boxes at $5). Aria solved it and verified by substitution โ a habit good problem-solvers keep.
x = 60 รท 5 = 12. Verify: substitute back, 5 ร 12 = 60. โ True, so 12 is correct.
Solve 7x = 84, then verify by substitution. What is x?
Why does Aria substitute her answer back into the equation?
Optional academic frame: "The equation models ______; solving gives ______, which I verified by ______."
The council needs at least $200 and sells tickets at $8 each. Write an inequality for the number of tickets t, and find the fewest whole tickets they must sell to reach the goal. Explain your reasoning. (Try it, then check with your teacher.)
| Category | 4 โ Advanced | 3 โ Proficient | 2 โ Developing |
|---|---|---|---|
| Comprehension & inference | All analysis questions correct; explains equation vs. inequality & verifying | 2 of 3 correct | 1 correct |
| Multi-step math | All 4 Solve-It answers correct (write+solve, solve, inequality, solve+verify) | 3 correct | 2 correct |
| Mathematical argument | Models a situation; solves, verifies, and explains balance/inequality | Claim with some evidence | Little evidence |