OCR C1 — Question 1 4 marks

Exam BoardOCR
ModuleC1 (Core Mathematics 1)
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicIndices and Surds
TypeEvaluate numerical powers
DifficultyEasy -1.8 This is a very routine C1 question testing basic manipulation of surds and negative indices. Part (i) requires simple rationalisation (dividing 21 by √7), and part (ii) is direct recall that 8^(-1) = 1/8. Both are standard textbook exercises with no problem-solving element, making this significantly easier than average A-level questions.
Spec1.02a Indices: laws of indices for rational exponents1.02b Surds: manipulation and rationalising denominators

  1. Express \(\frac{21}{\sqrt{7}}\) in the form \(k\sqrt{7}\). [2]
  2. Express \(8^{-1}\) as an exact fraction in its simplest form. [2]

\begin{enumerate}[label=(\roman*)]
\item Express $\frac{21}{\sqrt{7}}$ in the form $k\sqrt{7}$. [2]

\item Express $8^{-1}$ as an exact fraction in its simplest form. [2]
\end{enumerate}

\hfill \mbox{\textit{OCR C1  Q1 [4]}}