Q2 of 239 Page 29

Write down the unit digits of the following:

782

78 × 78


Let us only consider the unit’s digits of 78, which is 8.


8 × 8 = 64, which has 4 in its unit’s place.


This number is retained in the unit’s place when the digit is squared.


Hence the answer is 4.


More from this chapter

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6

Prove that

 1

Just observe the unit digits and state which of the following are not perfect squares.

i. 3136


ii. 3722


iii. 9348


iv. 2304


v. 8343

 2

Write down the unit digits of the following:

272

 2

Write down the unit digits of the following:

412