Free mental math practice for the SIG online assessment
A SIG-style speed-arithmetic simulator with 70 questions in 8 minutes, mixing typed and multiple-choice answers. It covers the three question families these assessments are known for: difference-of-squares products, decimal magnitude, and ugly fractions. TradeMind practice target: 55 net on this 70Q / 8-minute configuration (not a firm cutoff). Free, with no signup. The set is fixed: same questions, same order, every time.
70 questions · 8 minutes · mixed input
+1 per correct answer, −1 per wrong typed answer, −2 per wrong multiple-choice answer, skips are free. Typed difference-of-squares tricks plus 4-choice decimal-magnitude and ugly-fraction questions. TradeMind practice target: 55 net on this 70Q / 8-minute configuration (not a firm cutoff). Format and scoring may vary by region, role and recruiting cycle.
What this test is
Susquehanna International Group's quant hiring process is known for poker theory, expected-value thinking, and fast mental math. Candidates report that the arithmetic part rewards spotting shortcuts more than grinding through the computation. This simulator reconstructs that part as a timed 70-question set.
| Length | 70 questions · 8 minutes |
|---|---|
| Format | Mixed: typed answers (squares tricks) and 4-choice MCQ (decimals, fractions) |
| Scoring | +1 correct · −1 wrong typed · −2 wrong MCQ · 0 skipped |
| Practice target | TradeMind practice target: 55 net on this 70Q / 8-minute configuration (not a firm cutoff). Format and scoring may vary by region, role and recruiting cycle. |
| Content mix | 24 difference-of-squares · 24 decimal magnitude · 22 ugly fractions |
The three question families and the skill each tests
1. Difference of squares (shape recognition)
37 × 43, 19 × 21, 65 × 75: each is (a−b)(a+b) around a round base. The skill is noticing that symmetry in under a second. Drill until two numbers equidistant from a round number stand out before you have fully read them.
2. Decimal magnitude (counting zeros)
The digits are easy (15 × 4). The question is where the decimal point goes, and every distractor is the same digits shifted by a factor of ten. Most mistakes come from rushing the bookkeeping.
3. Ugly fractions (clean execution)
Prime denominators (3, 5, 7, 11) force full cross-multiplication. With a −2 MCQ penalty, work through all four small steps without shortcuts; the distractors are the answers the shortcuts produce.
Related practice
The full list is on the free tests page.
Questions
What is on the SIG online assessment?
Susquehanna (SIG) screens trading candidates with quantitative assessments that publicly available reports describe as heavy on speed arithmetic with a trick-recognition flavor: products like 19×21 that collapse via difference of squares, decimal-magnitude questions like 0.015×0.4 where the challenge is counting zeros, and fraction arithmetic with awkward prime denominators. This simulator drills those three families in 70 questions and 8 minutes. Its 55-net target is TradeMind's training setting, not a SIG cutoff.
What is the difference-of-squares trick?
Any product of the form (a−b)(a+b) equals a²−b². So 19×21 = 20²−1 = 399, and 45×55 = 50²−25 = 2475. Once you see two numbers straddling a round base symmetrically, the multiplication collapses into one square and one subtraction. SIG-style tests are known for rewarding candidates who recognise this shape instantly.
How do I get faster at decimal magnitude questions?
Separate the digits from the zeros. For 0.015 × 0.4: compute 15×4 = 60, then count decimal places (three + one = four), giving 0.0060 = 0.006. The multiple-choice distractors are always the same digits with the decimal point shifted, so the digit work is trivial and the question comes down to counting zeros carefully.
Why 'ugly' fractions?
Sums like 2/7 − 1/3 don't simplify nicely. The denominators are prime, so you have to work in 21sts. There's no trick; the test is clean cross-multiplication at speed. The classic distractors are the sign flip and the 'add straight across' answer, each one careless step away.
Is this the real SIG assessment?
No. It is an independent practice set focused on speed tricks, based on publicly reported SIG-style mental math. It is not a verified clone of any official SIG assessment. SIG's process varies by role and includes components beyond quick arithmetic, such as probability and game-theory questions. TradeMind is not affiliated with SIG.
TradeMind is an independent training tool and is not affiliated with, endorsed by, or sponsored by Susquehanna International Group (SIG) or any other firm mentioned. This simulator is a speed-tricks practice set inspired by publicly reported descriptions of SIG-style mental math, and is not a verified clone of any official assessment. Question content is procedurally generated and does not reproduce actual test material; live assessment formats, question types, and difficulty levels may evolve over time.