National Mathematics Day Challenge 2025 | Combined Answer Key - All Stages (NEP 2020) | Apex Edutech Solutions

🧠 National Mathematics Day – Answer Key

NEP 2020 | Competency-Based Learning | AIMS TODAY – Apex Edutech Solutions

Foundation Stage (Grades 1–2)

Q	Answer	Explanation
1	10	10 comes after 9.
2	7	7 is the biggest number.
3	3	A triangle has 3 sides.
4	8	8 is an even number.
5	Circle	A circle is round.
6	14	14 comes before 15.
7	3	There are 3 apples.
8	6	6 is smaller than others.
9	10	5 + 5 equals 10.
10	7	There are 7 days in a week.
11	0	0 represents nothing.
12	Book	A book has a square shape.
13	1	1 comes first.
14	5	We have 5 fingers.
15	7	7 is an odd number.
16	Ruler	A ruler is the longest.
17	20	20 comes after 19.
18	4	A square has 4 corners.
19	0	Zero means nothing.
20	Stone	A stone is heavy.
21	5	2 + 3 = 5.
22	9	9 comes before 10.
23	2	A bicycle has 2 wheels.
24	Square	A square has 4 sides.
25	8	8 is the greatest number.

Preparatory Stage (Grades 3–5)

Q	Answer	Explanation
1	50	5 is in tens place.
2	12	12 is divisible by 4.
3	6	36 ÷ 6 = 6.
4	2/4	2/4 equals 1/2.
5	7	7 has only two factors.
6	8	Pattern increases by 2.
7	Circle	A circle has one curved side.
8	200	125 + 75 = 200.
9	Metre	Used to measure length.
10	60	1 hour = 60 minutes.
11	20	20 is even.
12	36	9 × 4 = 36.
13	1/2	Largest fraction.
14	18	18 is divisible by 3.
15	20 cm	Perimeter = 4 × side.
16	90°	A right angle is 90°.
17	625	1000 − 375 = 625.
18	99	99 comes before 100.
19	Addition	Addition gives total.
20	1/5	Smallest fraction.
21	56	7 × 8 = 56.
22	5	Pentagon has 5 sides.
23	465	Largest number.
24	30	Half of 60.
25	Kilogram	Used to measure weight.

Middle Stage (Grades 6–8)

Q	Answer	Explanation
1	12	12 is divisible by both 2 and 3.
2	6	Highest common factor of 12 and 18 is 6.
3	49	7² means 7 × 7.
4	6/8	Multiplying numerator and denominator by 2.
5	180°	Sum of angles of a triangle is 180°.
6	29	29 has only two factors: 1 and 29.
7	30	Pattern follows n(n+1).
8	−2	−2 lies between −3 and −1.
9	26 cm	Perimeter = 2(l + b).
10	27	3³ = 3 × 3 × 3.
11	4 : 6	Multiply both terms by 2.
12	12	LCM of 4 and 6 is 12.
13	120°	Obtuse angle is greater than 90°.
14	30	15% of 200 = (15×200)/100.
15	Line Graph	Shows change over time.
16	9	Absolute value removes sign.
17	3x + 5	Expression with two terms.
18	36 cm²	Area = side × side.
19	25	5 × 5 = 25.
20	1/2	Probability of head.
21	Equilateral	All sides are equal.
22	3/4	0.75 = 75/100.
23	Brackets	BODMAS rule.
24	6	Mean = sum ÷ number.
25	3/5	Rational numbers can be written as fractions.

Secondary Stage (Grades 9–10)

Q	Answer	Explanation
1	12	√144 = 12.
2	x² − 4 = 0	Highest power of x is 2.
3	a² + 2ab + b²	Standard algebraic identity.
4	18	2 × 3² = 18.
5	√((x₂−x₁)²+(y₂−y₁)²)	Distance formula.
6	2x + 5 = 0	Linear equation has degree 1.
7	55	n(n+1)/2 formula.
8	1/2	sin 30° = 1/2.
9	3/4	Rational number.
10	14 cm	Diameter = 2 × radius.
11	43	27 + 16 = 43.
12	110° and 70°	Supplementary angles sum to 180°.
13	154 cm²	πr² = 22/7 × 7 × 7.
14	Straight line	y = mx + c is linear.
15	15	|−15| = 15.
16	1/2	Even numbers are 3 out of 6.
17	Pythagoras Theorem	Used in right-angled triangles.
18	Right-angled	3² + 4² = 5².
19	−8	(−2)³ = −8.
20	(a − b)² = a² − 2ab + b²	Correct algebraic identity.
21	1	tan 45° = 1.
22	5 and 9	No common factors.
23	3	Mean of first five natural numbers.
24	Co-prime	Numbers with no common factors.
25	3	3x − 9 = 0 ⇒ x = 3.