672 = 4489
6672 = 444889
= 44448889
666672 =
(111) As the ones place of 157n
square of the number will
ones place.
Check: 7 x 7 = 49.
1. Observing the above, we get
(i) 66672 = 44448889
(ii) 666672 = 4444488889
pe 2
Without actual addition, find the sum of the
following
Note
The square of a number having:
1 or 9 at the ones place ends in 1.
2 or 8 at the ones place ends in 4.
3 or 7 at the ones place ends in 9.
4 or 6 at the ones place ends in 6.
5 at the ones place ends in 5.
Factice Questions 6B
pe 1
Without actual multiplication, find the squares of:
(i) 1111111
(ii) 215
(iii) 95
(iv) 666667
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is this a question of English??
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Heya branliy user ! your answer
Prove that in a sequence of numbers 49,4489,444889,44448889…
elementary-number-theory
Prove that in a sequence of numbers 49,4489,444889,44448889… in which every number is made by 48 in the middle of previous as indicated, each number is the square of an integer.
MathGod
(610k−19+1)2=36102k−2⋅10k+181+1210k−19+1=410k−19⋅10k−410k−19+1210k−19+1=410k−19⋅10k+810k−19+1.
44...488...89 has n+1 numbers "4", n numbers "8", and the "9". So:
44...488...89=4⋅10n−19⋅10n+1+8⋅10n−19⋅10+9
Now, we say 10n=y so
4⋅(10y−1)⋅10y+8⋅10(y−1)+819=400y2+40y+19=(20y+13)2
Note that as y=(10n), 3|(20y+1), for any n value.
I hope it help for you Thanks ☺☺
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