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What will be the unit digit of the squares of the following numbers?
(i) 81   (ii) 272   (iii) 799   (iv) 3853   (v) 1234
(vi) 26387    (vii) 52698   (viii) 99880   (ix) 12796
(x) 55555

Solution:

(i) If a number has 1 or 9 in its unit digit, then its square ends with 1.

Since 81 has 1 as its unit digit, 1 will be the unit digit of its square. (1 × 1 = 1)

Similar Examples - 91, 721, 4321

(ii) If a number has either 2 or 8 as its unit digit, then its square ends with 4.

Since 272 has 2 as its unit digit, 4 will be the unit digit of its square. (2 × 2 = 4)

Similar Examples - 22, 2432, 147322

(iii) If a number has 1 or 9 in its unit digit, then its square ends with 1

Since 799 has 9 as its unit digit, 1 will be the unit digit of its square. (9 × 9 = 81)

(iv) If a number has either 3 or 7 as its unit digit, then its square number ends with 9.

Since 3853 has 3 as its unit digit, 9 will be the unit digit of its square. (3 × 3 = 9)

Similar Examples - 13, 433, 63

(v) If a number has either 4 or 6 as its unit digit, then its square ends with 6.

Since 1234 has 4 as its unit digit, 6 will be the unit digit of its square. (4 × 4 = 16)

Similar Examples - 14, 114, 484, 1594

(vi) If a number has either 3 or 7 as its unit digit, then its square number ends with 9.

Since 26387 has 7 as its unit digit, 9 will be the unit digit of its square. (7 × 7 = 49)

(vii) If a number has either 2 or 8 as its unit digit, then its square ends with 4.

Since 52698 has 8 as its unit digit, 4 will be the unit digit of its square. (8 × 8 = 64)

(viii) If a number has 0 as its unit digit, then its square ends with 0.

Since 99880 has 0 as its unit digit, 0 will be the unit digit of its square.

Similar Examples - 190, 1240, 167850

(ix) If a number has either 4 or 6 as its unit digit, then its square ends with 6.

Since 12796 has 6 as its unit digit, 6 will be the unit digit of its square. (6 × 6 = 36)

(x) If a number has 5 as its unit digit, then its square ends with 5.

Since 55555 has 5 as its unit digit, 5 will be the unit digit of its square. (5 × 5 = 25)

Similar Examples - 105, 85, 3425

☛ Check: NCERT Solutions for Class 8 Maths Chapter 6

Video Solution:

What will be the unit digit of the squares of the following numbers? (i) 81 (ii) 272 (iii) 799 (iv) 3853 (v) 1234 (vi) 26387 (vii) 52698 (viii) 99880 (ix) 12796 (x) 55555

NCERT Solutions for Class 8 Maths Chapter 6 Exercise 6.1 Question 1

Summary:

The unit digit of the squares of the following numbers (i) 81 (ii) 272 (iii) 799 (iv) 3853 (v) 1234 (vi) 26387 (vii) 52698 (viii) 99880 (ix) 12796 (x) 55555 will be (i) 1, (ii) 4, (iii) 1, (iv) 9, (v) 6, (vi) 9, (vii) 4, (viii) 0, (ix) 6, (x) 5

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