Practice Notation Overload in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

When the same symbol is used to mean different things in different contexts, requiring the reader to infer meaning from context.

The same word meaning different things in different conversations โ€” context tells you which meaning applies, but this can trip up a reader who is new to the context.

Showing a random 20 of 50 problems.

Example 1

medium
The symbol n!n! uses '!' for factorial. Compute 4!4!.

Example 2

medium
In a matrix context, โˆฃAโˆฃ|A| for A=(3124)A = \begin{pmatrix}3 & 1\\2 & 4\end{pmatrix} means the determinant. Compute it.

Example 3

hard
In abstract algebra, Z/nZ\mathbb{Z}/n\mathbb{Z} denotes the integers mod nn. For n=5n = 5, how many distinct elements are in this set?

Example 4

medium
The symbol (a,b)(a,b) can mean an open interval or an ordered pair. As a gcd, (8,12)(8,12) means gcdโก\gcd. Compute (8,12)(8,12) in that sense.

Example 5

easy
What does fโ€ฒ(x)f'(x) mean in calculus? For f(x)=x2f(x)=x^2, give fโ€ฒ(3)f'(3).

Example 6

challenge
In tensor calculus, TijT^{ij} vs TijT_{ij} vs TjiT^i_j all denote different things. What standard convention disambiguates them?

Example 7

challenge
In anka_n^k, what's the difference between kk as an index and kk as an exponent? Give an example where this distinction matters.

Example 8

easy
In the context {1,2,3}\{1, 2, 3\}, what does {}\{\} mean?

Example 9

hard
In f(x)=x2f(x) = x^2, the parentheses denote function application. In (x+1)2(x+1)^2, what do the parentheses denote? Compute when x=3x=3.

Example 10

challenge
(nk)\binom{n}{k} and C(n,k)C(n,k) both denote combinations, but 'nCrnCr' on a calculator is the same. Compute (52)\binom{5}{2}.

Example 11

medium
The superscript in Tโˆ’1T^{-1} for a matrix means inverse, while ATA^T means transpose. For A=(1234)A=\begin{pmatrix}1&2\\3&4\end{pmatrix}, give the top-left entry of ATA^T.

Example 12

easy
The symbol โˆฃโ‹…โˆฃ|\cdot| is used for absolute value of numbers and cardinality of sets. Evaluate: (a) โˆฃโˆ’3โˆฃ|-3|, (b) โˆฃ{1,2,3}โˆฃ|\{1,2,3\}|.

Example 13

medium
logโกx\log x can mean base-10, base-ee, or base-2 depending on field. In CS texts, it usually means base what?

Example 14

medium
In the expression sinโก2x\sin^2 x, the superscript 22 means what? Compute sinโก2(ฯ€/6)\sin^2(\pi/6).

Example 15

medium
The symbol โˆ—\ast can mean: (1) multiplication, (2) convolution, (3) a generic binary operation. For each usage, give one example context.

Example 16

challenge
Translate carefully: the statement 'โˆฃGโˆฃ=6|G| = 6 and GG is generated by elements satisfying a3=ea^3 = e and b2=eb^2 = e.' What does each symbol mean?

Example 17

medium
Set-builder {xโˆˆRโˆฃx>0}\{x \in \mathbb{R} \mid x > 0\}: what does the โˆฃ\mid mean?

Example 18

easy
In the integral โˆซabf(x)โ€‰dx\int_a^b f(x)\, dx, what does dxdx mean?

Example 19

medium
Decide what (2,5)(2, 5) means in each context: (i) coordinate plane; (ii) interval on the real line. For (ii), is 33 in the set?

Example 20

easy
In Rn\mathbb{R}^n, what does the superscript nn mean?