🔓 The heist case — four locks, four kinds of thinking

The Villain's Vault — a K–5 Common Core Math Mystery

The Villain's Vault is the most mechanical of the six, and the most satisfying for a child who likes machines. Our stolen case files are behind a four-layer vault, and each layer is a genuinely different puzzle rather than the same question in a new coat — a laser grid, a balance scale, a bank of interlocking gears, a trip-wire alarm. It is the only mystery whose four mechanics stay the same from Kindergarten all the way to Grade 5, which sounds like a limitation and is actually the point: the cadet learns the machine once, then meets it again each year with harder mathematics inside it. The gear works that ask a five-year-old to count by tens ask a ten-year-old to divide.

Launch the case → See plans

The case

The villain locked our stolen case files behind a four-layer vault. Beat four fiendish defences — laser grid, bullion balance, gear works and trip-wire alarm — to recover the files and unmask the thief.

The four clue rounds

Each round is a different interactive mechanic — not the same question in a new coat. Crack all four to unmask the culprit.

The Villain's Vault at every grade, K–5

The same story, re-levelled for each grade against its own Common Core standards. Pick your child's grade:

GradeSkill focusStandardsXP
Kindergarten Count, add within 10 & count by tens K.CC.B.5 K.OA.A.2 K.CC.A.1 K.CC.C.7 ⚡ 100 XP Launch →
Grade 1 Tens & ones, equality & compare 1.NBT.B.2 1.OA.D.7 1.NBT.C.5 1.NBT.B.3 ⚡ 110 XP Launch →
Grade 2 Even/odd, arrays, compare, +/− 2.OA.C.3 2.NBT.B.5 2.OA.C.4 2.NBT.A.4 ⚡ 130 XP Launch →
Grade 3 Multiples, place value & fractions 3.OA.C.7 3.NBT.A.2 3.OA.A.1 3.NF.A.3.d ⚡ 140 XP Launch →
Grade 4 Factors & primes, multi-digit + × 4.OA.B.4 4.NBT.B.4 4.NBT.B.5 4.NBT.A.2 ⚡ 150 XP Launch →
Grade 5 Expressions, decimals & division 5.OA.A.1 5.NBT.B.7 5.NBT.B.6 5.NBT.A.3 ⚡ 160 XP Launch →

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Every Common Core standard in this case

Across K–5, The Villain's Vault covers these 24 standards. Mastery is tracked per standard for each agent. Official Common Core wording:

1.NBT.B.2Understand that the two digits of a two-digit number represent amounts of tens and ones.
1.NBT.B.3Compare two two-digit numbers based on meanings of the tens and ones digits, recording the results of comparisons with the symbols >, =, and <.
1.NBT.C.5Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
1.OA.D.7Understand the meaning of the equal sign, and determine if equations involving addition and subtraction are true or false.
2.NBT.A.4Compare two three-digit numbers based on meanings of the hundreds, tens, and ones digits, using >, =, and < symbols to record the results of comparisons.
2.NBT.B.5Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.
2.OA.C.3Determine whether a group of objects (up to 20) has an odd or even number of members, e.g., by pairing objects or counting them by 2s; write an equation to express an even number as a sum of two equal addends.
2.OA.C.4Use addition to find the total number of objects arranged in rectangular arrays with up to 5 rows and up to 5 columns; write an equation to express the total as a sum of equal addends.
3.NBT.A.2Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.
3.NF.A.3.dCompare two fractions with the same numerator or the same denominator by reasoning about their size. Recognize that comparisons are valid only when the two fractions refer to the same whole. Record the results of comparisons with the symbols >, =, or <, and justify the conclusions, e.g., by using a visual fraction model.
3.OA.A.1Interpret products of whole numbers, e.g., interpret 5 × 7 as the total number of objects in 5 groups of 7 objects each.
3.OA.C.7Fluently multiply and divide within 100, using strategies such as the relationship between multiplication and division or properties of operations. By the end of Grade 3, know from memory all products of two one-digit numbers.
4.NBT.A.2Read and write multi-digit whole numbers using base-ten numerals, number names, and expanded form. Compare two multi-digit numbers based on meanings of the digits in each place, using >, =, and < symbols to record the results of comparisons.
4.NBT.B.4Fluently add and subtract multi-digit whole numbers using the standard algorithm.
4.NBT.B.5Multiply a whole number of up to four digits by a one-digit whole number, and multiply two two-digit numbers, using strategies based on place value and the properties of operations. Illustrate and explain the calculation by using equations, rectangular arrays, and/or area models.
4.OA.B.4Find all factor pairs for a whole number in the range 1—100. Recognize that a whole number is a multiple of each of its factors. Determine whether a given whole number in the range 1—100 is a multiple of a given one-digit number. Determine whether a given whole number in the range 1—100 is prime or composite.
5.NBT.A.3Read, write, and compare decimals to thousandths.
5.NBT.B.6Find whole-number quotients of whole numbers with up to four-digit dividends and two-digit divisors, using strategies based on place value, the properties of operations, and/or the relationship between multiplication and division. Illustrate and explain the calculation by using equations, rectangular arrays, and/or area models.
5.NBT.B.7Add, subtract, multiply, and divide decimals to hundredths, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.
5.OA.A.1Use parentheses, brackets, or braces in numerical expressions, and evaluate expressions with these symbols.
K.CC.A.1Count to 100 by ones and by tens.
K.CC.B.5Count to answer "how many?" questions about as many as 20 things arranged in a line, a rectangular array, or a circle, or as many as 10 things in a scattered configuration; given a number from 1—20, count out that many objects.
K.CC.C.7Compare two numbers between 1 and 10 presented as written numerals.
K.OA.A.2Solve addition and subtraction word problems, and add and subtract within 10, e.g., by using objects or drawings to represent the problem.

Questions parents and teachers ask

What makes this different from the other mysteries?

Its four mechanics are identical at every grade — only the mathematics inside them changes. That makes it the best case for a child who's returning year after year, because the interface never has to be relearned.

Is a vault heist too dark for young children?

It's played for fun, not menace — the villain is a cartoon and the stakes are stolen paperwork. There's no peril, no violence, and no scary imagery.

Do you need a membership for this one?

Yes. Starlight Station is the free case; The Villain's Vault and the other four unlock with a membership.

The other mysteries

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