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NumBlitz

A free math streak game by Think Again

How long can your streak last?

Pick a category and answer as many questions as you can. You have 10 seconds for each one. One wrong answer ends the run, and the questions get harder as you go.

  • 10 seconds per question
  • One mistake ends the run
  • Easy, then medium, then hard
Choose a category

No sign-up. No download. Just think.

See today's top streaks

How to play

  1. 1Choose a category, or press Surprise me.
  2. 2You have 10 seconds for each question. Tap an answer, or press 1, 2, 3 or 4.
  3. 3Each correct answer adds one to your streak. The questions get harder as you go: easy at first, medium from question 7 and hard from question 14.
  4. 4One wrong answer, or running out of time, ends the run. You then see the right answer and a short explanation.
  5. 5Post your streak to the daily and weekly leaderboards with a nickname and a country flag.

Try a few questions

These are real questions from the game. Think first, then open the answer.

Arithmetic

Quick mental math: sums, products, percentages, fractions and powers.

What is 75% of 40?

  1. 60
  2. 15
  3. 30
  4. 10
Show the answer

Answer: C — 30

25% of 40 is 10, so 75% is 3 × 10 = 30.

What is 36 ÷ 4 + 2 × 5?

  1. 55
  2. 30
  3. 21
  4. 19
Show the answer

Answer: D — 19

Divide and multiply before adding: 36 ÷ 4 = 9 and 2 × 5 = 10. Then 9 + 10 = 19.

Algebra

Solve equations, expand brackets and work with expressions, step by step.

Solve for x:
2x + 5 = 17

  1. 11
  2. 12
  3. 7
  4. 6
Show the answer

Answer: D — 6

Take 5 away from both sides: 2x = 12. Then divide by 2: x = 6.

Expand: 2(3x − 5)

  1. 6x + 10
  2. 6x − 10
  3. 6x − 5
  4. 3x − 10
Show the answer

Answer: B — 6x − 10

Multiply each term inside by 2: 3x becomes 6x, and −5 becomes −10. So it is 6x − 10.

Probability

Coins, dice, cards and marbles: how likely is it?

This spinner has 4 equal parts: 2 red, 1 blue and 1 green. What is the probability that the arrow stops on red?

  1. 1/3
  2. 1/4
  3. 3/4
  4. 1/2
Show the answer

Answer: D — 1/2

2 of the 4 equal parts are red, so the probability is 2/4 = 1/2.

You flip two coins. What is the probability that both show heads?

  1. 1/2
  2. 3/4
  3. 1/4
  4. 1/3
Show the answer

Answer: C — 1/4

The 4 equally likely results are HH, HT, TH and TT (H = heads, T = tails). Only HH works: 1/4.

Geometry

Areas, angles, circles and right triangles, with a drawing for most questions.

What is the missing angle?

  1. 70°
  2. 250°
  3. 110°
  4. 80°
Show the answer

Answer: A — 70°

The angles of a triangle add up to 180°. 180° − 50° − 60° = 70°.

What is the missing length?

  1. 15
  2. 21
  3. 225
  4. 16
Show the answer

Answer: A — 15

It is the 3-4-5 triangle times 3. Check: 9² + 12² = 81 + 144 = 225 = 15².

Logic Puzzles

Classic puzzles and brain teasers that reward careful thinking.

Today is Wednesday. What day will it be in 10 days?

  1. Monday
  2. Saturday
  3. Friday
  4. Sunday
Show the answer

Answer: B — Saturday

10 days = 1 week + 3 days. Whole weeks bring you back to Wednesday, so count 3 days forward: Saturday.

Ana has 3 brothers. Each of her brothers has 2 sisters. How many sisters does Ana have?

  1. 1
  2. 2
  3. 6
  4. 3
Show the answer

Answer: A — 1

The 2 sisters of each brother are Ana and one more girl. So Ana has 1 sister.

Number Patterns

Find the rule, then the next number, in sequences of every kind.

What number comes next?
3, 7, 11, 15, ?

  1. 23
  2. 18
  3. 20
  4. 19
Show the answer

Answer: D — 19

Each number is 4 more than the one before. 15 + 4 = 19.

What number comes next?
100, 99, 97, 94, 90, ?

  1. 84
  2. 87
  3. 85
  4. 86
Show the answer

Answer: C — 85

The jumps are −1, −2, −3, −4, so the next jump is −5: 90 − 5 = 85.

Questions and answers

Is NumBlitz free?
Yes. It is free to play, with no account and nothing to download.
Who is it for?
Anyone who enjoys numbers: students, parents, teachers and puzzle fans of every age. The first questions are easy, so everyone can start a streak.
How does the leaderboard work?
After a run you can post your streak with a nickname and a flag. The daily board starts again every day at 00:00 UTC, and the weekly board every Monday at 00:00 UTC.
Can I play in Spanish?
Yes. Use the EN / ES switch at the top of the page. Every question and every explanation is translated.
Where do the questions come from?
Every question was written for NumBlitz, and every answer was checked twice.
Who makes NumBlitz?
Think Again, a free educational YouTube channel about math puzzles and surprising ideas.