3 Strategies to Tackling Multiple Choice questions

1. 3 Strategies to Tackling Multiple Choice questions • Plug in a number • Back-solving • Guessing

2. Tackling Multiple Choice Questions • Plug in/Pick a number: • If there are variables in the answer choices, students should consider using the Pick a Number strategy. • Here's how it works: • Pick numbers for each of the variables. • Plug the numbers into the question and find the result. • Next, substitute the numbers for the variables in each answer choice. • Now simplify each answer choice and compare the results to the original value.

3. Plug in/Pick a number Using Pick a Number If s skirts cost d dollars, how much would s - 1 skirts cost?A. d - 1B. d - sC. d / s - 1D. d(s - 1) / s- What numbers did you select to represent the two variables?- Using these values, how much would s - 1 skirts cost?- Which answer choice matches this cost?

4. Plug in/Pick a number Tips for Picking a Number • Pick small numbers that are easy to work with. • When there are two variables, pick different numbers for each. • Avoid picking 0 or 1, as these often give several "possibly correct" answers. Plug carefully • When plugging values in for variables, make sure you are using the right number for each variable.

5. PRACTICE: Plug in/Pick a number

6. Explanation: Plug in/Pick a number

7. PRACTICE: Plug in/Pick a number

8. Explanation: Plug in/Pick a number

9. Tackling Multiple Choice Questions • Back-solving • Use when picking numbers and solving the problem isn’t possible • Work back-wards using answer choices

10. Back-solving • How to back-solve • Plug choices back into the question until you find the one that fits • Answer choices are arranged in order, either descending or ascending from (A) to (E) • Choose choice (C) first to plug into the equation to guide your next step • If it gives you too small an answer, then (A) and (B) or (D) and (E) can be eliminated depending on which values are smaller than (C)

11. Back-solving • When to back-solve • Question is a complex word problem & answer choices are numbers • The alternative is to set up multiple algebraic equations • When back-solving isn’t ideal • Answer choices include variables • Algebra quest. And word problems that have ugly answer choices (radicals, fractions)

12. Practice with Back-Solving

14. Practice with Back-Solving

16. Tackling Multiple Choice Questions • Guessing • Avoid random guessing • Make educated guesses • Eliminate unreasonable answer choices • Eliminate the obvious answers on hard questions • Eyeball lengths, angles, and areas on geometry questions

17. Guessing • Eliminate unreasonable answer choices • Which answers don’t make sense • Eliminate the obvious on hard questions • Obvious answers are usually wrong for hard questions • Don’t use this for easy questions, the obvious answer might be right

18. Guessing • Eyeballing lengths, angles, & areas • Use diagrams to help you eliminate wrong answer choices • Double check to see if the diagram is drawn to scale • If it’s not drawn to scale, you can’t use this strategy—figures are drawn to scale unless otherwise noted • If it is, estimate quantities or eyeball the diagram, angle, length, or area

19. Guessing • Eyeballing lengths, angles, & areas • eliminate answer choices that are too large or too small • With angles, compare them to 180°, 90°, or 45° angles • Use the corner of a piece of paper (right angle) to see if an angle is > or < 90° • With areas, compare an unknown area to an area that you do know

20. PRACTICE GUESSING

26. Grid-In Questions • No answer choices • 4 boxes and a column of ovals, or bubbles to write your answer • No penalty for wrong answers

27. Grid-In Questions • Some questions have only 1 correct answer, others have several • Digits, decimal points, fraction signs should be written in separate boxes • Bubble in underneath

28. Grid-In Questions • You can’t grid • Negative numbers • Answers with variables • Answers greater than 9,999 • Answers with commas (1000 not 1,000) • Mixed numbers (ex: 2 ½)

29. Grid-In Strategies • Write (.7 not 0.7) • Grid fractions in the correct column • Ex: 31/42 won’t fit & will need to be converted into a decimal • Place decimal points carefully • If decimal <1, enter the decimal point in the 1st column (.127) • Only grid in a 0 before the decimal if it is part of the answer (20.5) • Never grid a decimal point in the last column

30. Grid-In Strategies • Long or repeating decimals • Grid the first 3 digits only and plug in the decimal point • Rounding to an even shorter answer may be incorrect – try not to round • If there is more than 1 right answer, choose 1 and enter it

31. Grid-In Strategies • If the answer has a range of possible answers, grid any value between that range • It’s easier to work with decimals • Ex: 1/3 < m < ½ • Don’t grid 1/3 or ½ -- that would be wrong • Grid .4 or .35 or .45 • Check your work

32. Using Calculators • Help the most on Grid-ins • Use it only to save time • If you can’t think of a reason why using a calculator would make a problem easier or quicker to solve, don’t use it

33. Using Calculators • Think first • Decide on the best way to solve the problem • Only then, use your calculator • Check your answers • Be sure that calculations involving parenthesis are correct before pressing “enter” • Don’t forget PEMDAS • Parenthesis, exponent, multiply, divide, add, subtract

34. GRID IN PRACTICE 1 There are 12 men and 24 women in a chorus. What percent of the entire chorus is composed of women? (Disregard the percent sign when gridding your answer). 12+ 24= 36 24/36= 66.66666666 66.6 OR 66.7

35. GRID IN PRACTICE 2 Note: figure not drawn to scale If x and y are integers and x > 90, what is the minimum possible value of x ? One way to reason through this problem is as follows. The interior angles of a triangle add up to 180�. So x + y + 3y = 180, or x + 4y = 180. Try the smallest integer value of x greater than 90 in this formula, that is, x = 91. This gives , so . Thus if x = 91, . But y must be an integer, so x must be a larger number. Try the next greater integer value for x. If x = 92, then , so , which means that . Since y is an integer in this case, the minimum value of x is 92. 92

36. GRID IN PRACTICE 3 A gumball machine dispenses gumballs of different colors in the following pattern: green, blue, red, red, yellow, white, white, green, and green. Assuming the pattern repeats itself, if the machine dispenses 60 gumballs, how many of them will be green? This is a classic pattern question—with a twist. The key here is to count the number of elements in the given pattern. This pattern has 9 elements that repeat. Of these, three are green. So every time the machine goes through the pattern, 3 of the gumballs it dispenses are green. 60 is not a multiple of 9, but 54 is. When the machine is up to the 54th gumball, it will have gone through this pattern of 9 exactly 6 times. So it will have dispensed green gumballs. For the remaining 6, just count into the pattern. Only one more green gumball will be dispensed 19