Logical Reasoning

PT16 · S2 · Q6 The introduction of symbols for numbers

A free, expert breakdown of this official LSAT Logical Reasoning question.

  • Save & drill this skill — build targeted practice sets from questions like this one

  • Video walkthroughs — watch every question solved step by step

  • 81 official LSATs — as questions, timed sections & full-length tests

Start practicing free

The introduction of symbols for numbers is an event lost in prehistory, but the earliest known number symbols, in the form of simple grooves and scratches on bones and stones, date back 20,000 years or more.

Your task

Find the assumption the argument requires in order for its conclusion to hold.

Common trap

Answers that would help the argument but aren't strictly required (sufficient, not necessary).

Winning move

Negate each choice — the right one breaks the argument when negated.

6.

Which one of the following is an assumption on which the argument relies?

  1. Grooves and scratches found on

    Trap

    2% picked this

  2. Some kinds of surfaces upon

    Trap

    7% picked this

  3. Grooves and scratches inscribed on

    Trap

    1% picked this

  4. Correct

    Computation of any sort required

    Why this is right

    Answer D is correct.

    Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.

    86% picked this

  5. Systematic methods for writing numerals

    Trap

    4% picked this

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill
LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free