Calculator Strategies

SAT Math has two sections:

Section 3: No Calculator (25 minutes, 20 questions)

• Tests mental math and algebraic reasoning
• Problems are designed to be solved without a calculator
• Simpler arithmetic, but requires strong number sense

Section 4: Calculator Allowed (55 minutes, 38 questions)

• Calculator is permitted but NOT always needed
• Many questions are faster WITHOUT a calculator
• Calculator helps most with: statistics, complex arithmetic, graphing

Key insight: Having a calculator doesn't mean you should use it for every problem. Many "calculator-allowed" questions are faster by hand.

Answer: Section 3 = No Calculator, Section 4 = Calculator Allowed.

USE your calculator for:

1. Complex arithmetic — large numbers, decimals, fractions
2. Graphing — finding intersections, zeros, or behavior of functions
3. Statistics — mean, standard deviation, regression
4. Checking work — plug your answer back in
5. Trigonometry — when exact values aren't expected

DON'T use your calculator for:

1. Simple algebra — solving $2x + 5 = 11$ is faster by hand
2. Factoring — $x^2 + 5x + 6 = (x+2)(x+3)$ is faster mentally
3. Estimation — "approximately how many..." questions
4. Conceptual questions — "which graph represents..."
5. Unit conversion — set up the ratios first

Rule of thumb: If you can solve it in under 15 seconds by hand, don't pick up the calculator. Time spent entering numbers is time wasted.

Answer: Use calculators for complex computation; avoid for simple algebra and conceptual questions.

Method 1: Graph and find zeros

1. Enter $Y_1 = x^2 - 5x + 6$
2. Graph the function
3. Find where the graph crosses the x-axis (zeros/roots)
4. Use the ZERO function (2nd → CALC → 2:zero)
5. The zeros are $x = 2$ and $x = 3$

Method 2: Table

1. Enter $Y_1 = x^2 - 5x + 6$
2. Go to TABLE (2nd → TABLE)
3. Look for y-values of 0
4. At $x = 2$: $y = 0$ ✓
5. At $x = 3$: $y = 0$ ✓

Method 3: Solver (some calculators) Enter the equation and let the calculator solve.

By hand (faster for this problem!): $x^2 - 5x + 6 = (x-2)(x-3) = 0$ $x = 2$ or $x = 3$

Lesson: For simple quadratics, factoring by hand is faster. Use the calculator for complex quadratics that don't factor easily.

Answer: $x = 2$ and $x = 3$

Calculator method:

Step 1: Enter both functions:

• $Y_1 = x^3 - 4x$
• $Y_2 = x^2 - 4$

Step 2: Graph both and find intersections:

• Use 2nd → CALC → 5:intersect
• Move cursor near each intersection point
• Press ENTER three times to find each intersection

Algebraic verification: Set equal: $x^3 - 4x = x^2 - 4$ $x^3 - x^2 - 4x + 4 = 0$ Factor: $x^2(x - 1) - 4(x - 1) = 0$ $(x^2 - 4)(x - 1) = 0$ $(x-2)(x+2)(x-1) = 0$ $x = 2, x = -2, x = 1$

Find y-values:

• $x = 2$: $y = 4 - 4 = 0$ → Point: $(2, 0)$
• $x = -2$: $y = 4 - 4 = 0$ → Point: $(-2, 0)$
• $x = 1$: $y = 1 - 4 = -3$ → Point: $(1, -3)$

Answer: Three intersection points: $(2, 0)$, $(-2, 0)$, and $(1, -3)$.

Don't panic. Here's your debugging checklist:

Step 1: Re-read the question

• Did you answer what was actually asked? (Common: solving for $x$ when they want $2x$, or finding the value when they want the number of solutions)
• Check: "What is the value of $2x + 1$?" → If $x = 3.5$, then $2(3.5) + 1 = 8$ ✓

Step 2: Check your arithmetic

• Re-enter calculations in your calculator
• Check for sign errors
• Verify you copied the problem correctly

Step 3: Check your setup

• Did you read the problem correctly?
• Did you use the right formula?
• Did you set up the equation properly?

Step 4: Try plugging in the answer choices

• This is called "backsolving" — a powerful SAT strategy
• Try the middle value first, then adjust up or down
• This can be faster than solving algebraically

Step 5: Consider the student-produced response format

• If it's a grid-in question, 3.5 might actually be the correct answer!
• Grid-in answers CAN be non-integers: fractions and decimals are valid

Answer: Re-read the question (you may need a different expression), check your work, or try backsolving from the answer choices.