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DSSSB TGT C9sumnaturals — practice questions

Explore 8 free C9sumnaturals questions in DSSSB TGT Mathematics. Open each question or exercise to read its content, reference answers and available explanation.

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C9sumnaturals questions and exercises with answers

Showing questions 1–8 of 8.

As per your syllabus, Math, what is the FORMULA for the sum of the first n natural numbers?Read the answer and worked solution →As per your syllabus, the sum of the first 10 natural numbers (1 + 2 +... + 10) equals which value?Read the answer and worked solution →As per your syllabus, the sum 1 + 2 + 3 +... + 100 equals which value?Read the answer and worked solution →As per your syllabus, the nth TRIANGULAR NUMBER tₙ (1, 3, 6, 10, 15,...) equals the sum of the first n natural numbers — so the formula is which?Read the answer and worked solution →As per your syllabus, what is the 10th triangular number using tₙ = n(n+1)/2?Read the answer and worked solution →As per your syllabus, the sum 25 + 26 + 27 +... + 58 can be computed as which expression?Read the answer and worked solution →As per your syllabus, a child arranges marbles in rows: 1 marble in row 1, 2 in row 2, 3 in row 3,..., 25 in row 25. How many marbles total?Read the answer and worked solution →As per your syllabus, what is the sum of the first 20 natural numbers (1 + 2 +... + 20)?Read the answer and worked solution →

Worked practice questions

As per your syllabus, Math, what is the FORMULA for the sum of the first n natural numbers?

  1. Sₙ = (n + 1)² / 2
  2. Sₙ = n(n + 1) / 2
  3. Sₙ = n²
  4. Sₙ = n(n − 1) / 2
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Correct answer: B. Sₙ = n(n + 1) / 2

As per your syllabus, Sₙ = 1 + 2 +... + n = n(n+1)/2. The other formulas misstate.

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As per your syllabus, the sum of the first 10 natural numbers (1 + 2 +... + 10) equals which value?

  1. 45
  2. 100
  3. 110
  4. 55 (= 10 × 11 / 2)
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Correct answer: D. 55 (= 10 × 11 / 2)

As per your syllabus, S₁₀ = 10 × 11 / 2 = 55.

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As per your syllabus, the sum 1 + 2 + 3 +... + 100 equals which value?

  1. 10000
  2. 5000
  3. 1010
  4. 5050 (= 100 × 101 / 2)
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Correct answer: D. 5050 (= 100 × 101 / 2)

As per your syllabus, S₁₀₀ = 100 × 101 / 2 = 5050.

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More Mathematics topics

SequencesBinomial TheoremGeometryProbability & StatisticsSequences and SeriesVectors & 3D GeometryProbabilityCorrelation and Regression