Probability Flip Practice
Probability flip questions ask for the chance that something is not a particular colour or type. The key is to count the whole set, subtract the target group, and write the remaining chance as a fraction.
The Rules Every Probability Flip Question Uses
These questions all use the complement rule: instead of counting the colour named in the question, count everything that is not that colour.
𧎠Rule 1: Count the total first
Add every group in the bag before thinking about the named colour.
Example: 7 silver + 8 gold + 10 bronze = 25 cubes.
đ¯ Rule 2: Identify the target group
The target group is the colour or type after the word NOT.
Example: For "NOT gold", gold is the target group.
âŠī¸ Rule 3: Flip with subtraction
Subtract the target count from the total to find the number that are not the target.
Example: 25 total - 8 gold = 17 not gold.
ÂŊ Rule 4: Simplify the fraction
The probability is the not-target count over the total count. Simplify if possible.
Example: 2028 simplifies to 57.
How to Solve Probability Flip Questions
Three useful moves: add the total, subtract the named group, then simplify the probability fraction.
1. Count What Is Not Gold
Question: A bag contains 7 silver cubes, 8 gold cubes and 10 bronze cubes. One cube is picked at random. What is the probability that the cube is NOT gold?
Probability = 1725
Worked Method
Step 1: Total cubes = 7 + 8 + 10 = 25.
Step 2: Gold cubes = 8.
Step 3: NOT gold = 25 - 8 = 17.
Tip: Probability = 17 out of 25, so the answer is 1725.
2. Simplify the Answer
Question: Jenny has 12 silver gems, 8 gold gems and 8 bronze gems in a bag. One gem is drawn at random. What is the probability that the gem is NOT bronze?
Probability = 2028 = 57
Worked Method
Step 1: Total gems = 12 + 8 + 8 = 28.
Step 2: Bronze gems = 8.
Step 3: NOT bronze = 28 - 8 = 20.
Tip: Probability = 2028, which simplifies to 57.
3. Do Not Use the Target Count
Question: There are 4 pink counters, 4 black counters and 12 white counters in a bag. One counter is drawn at random. Find the probability that it is NOT black.
Probability = 1620 = 45
Worked Method
Step 1: Total counters = 4 + 4 + 12 = 20.
Step 2: Black counters = 4.
Step 3: NOT black = 20 - 4 = 16.
Tip: The answer is not 420. That is the chance of black. NOT black is 1620 = 45.
Before You Buy
Want to check the level and layout first? Download the free 3-question sample. It uses the same question style, printable format, and answer-key approach as the full pack.
Download Free Sample PDFGet the Full Practice Pack
The full Probability Flip pack contains 90 questions across 3 printable test sets. Students practise NOT probability questions, complement counts, probability fractions, and simplifying answers.
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