Grade 8 Probability Worksheets — Free Printable PDF
Grade 8 probability rests on two facts that do a great deal of work. Everything that could happen has a total probability of one, so a missing outcome can always be recovered from the others. And when two things both have to happen, their probabilities multiply — with the important catch that the second stage may not look like the first.
These sheets work both in words. A bag of three red and five blue counters, drawn from twice without putting the first back, gives 3/28 — and the reason it is not 9/64 is the whole of the second idea.
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Probability · Grade 8
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Grade 8 · 3 pages · A4More Grade 8 probability skills
Each one generates a different kind of question, with its own three levels and answer key.
What each level generates
Grade 8 probabilities that sum to one — the exact skill behind each difficulty setting, straight from the generator.
- Level 1One missing of three
- Level 2One missing of four
- Level 3The rest, shared equally
Grade levels follow the progression common to most English-language curricula — not one specific national curriculum. Every level shows exactly what it generates, so you can check the fit with your own program. See the full scope & sequence →
With and without replacement
The two-stage sub-skill runs both cases and the third level is the one that matters. If the counter goes back, the bag is identical for the second draw and the two probabilities are the same. If it does not, both the top and the bottom of the second fraction change: one fewer of the colour taken, and one fewer counter in total.
A child who gets 9/64 where the answer is 3/28 has almost always multiplied the same fraction twice out of habit. It is worth writing the second fraction out separately before multiplying, every time, until the difference stops needing to be remembered.
Where Grade 8 probability sits in the curriculum
US Common Core's Grade 8 Statistics and Probability standards are about bivariate data — scatter plots, lines of fit, and two-way tables — not probability. So a page of Grade 8 probability is not Common Core Grade 8 content, and this site does not claim it is; under Common Core these ideas extend the Grade 7 work at 7.SP.C.
They are squarely placed elsewhere. The Australian Curriculum's Year 8 strand names complementary events summing to one and determining probabilities for two-stage events, Ontario's Grade 8 expectations cover multi-event probability, and England's Key Stage 3 states explicitly that the probabilities of all possible outcomes sum to 1.
Frequently asked questions
▸Does Common Core cover probability at Grade 8?
Not as probability. The Grade 8 Statistics and Probability standards cover scatter plots, lines of best fit and two-way tables. These sheets carry the Grade 7 probability work forward, in step with the Australian Year 8 and Ontario Grade 8 chance strands and England's Key Stage 3.
▸How do you find a missing probability?
Subtract the ones you have from one, since every possible outcome together must total one. On the third level the remainder is then shared equally between two outcomes, so there is a halving after the subtraction.
▸What does 'without replacement' change?
Both parts of the second fraction. Taking a red counter from three red and five blue leaves two red out of seven, so the second probability is 2/7 and not 3/8. Multiplying gives 3/28.
▸Are there tree diagrams to fill in?
No — every question is set out in a sentence and answered with a single probability. A tree is a good way to organise the work and your child can draw one on scrap paper, but nothing on the sheet requires it.
▸Is this worksheet generator free?
Yes — free, no sign-up, and no watermark. The link in the address bar reprints the identical sheet whenever you want it.