Page 43 - SM inner class 8.cdr

A
-
+
9A = 325 300 29 300 + 70 + 11 + 4 = 407
54 11A = 33
9A = 25 29 Þ 9A = 54 ÞA = = 6
+
9 A = 3
Therefore, A = 6 Example 10. Find the value of the letters in the
given multiplication
Example 9. Find A in the addition
17 A AB
´ 5
+ 2 A 4
CAB
4 0 7
Solution : If we take B = 0 or 1 or 5 then 0 ´ 5 =
Solution : By observation A + 4 = 7.
or 100 + 70 + A 0, 1 ´ 5 = 5, 5 ´ 5 = 25
If B = 0, then A0 ´ 5 = CA0
Hence, A = 3 200 + 10A + 4
then if we take A = 5, then 50 ´ 5 = 250
173 + 234 = 407
\ CAB = 250
E xercise 5.2

1. Find the miss ing digits in the follow ing addi tions:.
(i) 111 (ii) 222 (iii) A A A (iv) 2222
A - 8 + 7 + 99
+ 77 + A A + AA + 9
197 313 373 A A A
299 A
(v) BB
+ 6
A A A
461

2. Find the value of A in the follow ing:
(i) 7A - 16 = A9 (ii) 107 - A9 = 1A (iii) A36 - 1A4 = 742
3. Find the numer i cal value of the letters given below-
(i) (ii)
D E G H
´ 3 ´ 6
F D E C G H
4. Replace the letters with appro pri ate digits
(i) 73K ÷ 8 = 9L (ii) 1MN ÷ 3 = MN
5. If ABB ´ 999 = ABC123 (where A, B, C are digits) find the values of A, B, C.

6. In BA ´ B3 = 57A. BA, B3 are two digit numbers and 57A is a 3 digit number. Then find A and B.

Factors and Multiples of numbers:
The factors of 36 are 1, 2, 3, 4, 6, 9, 12, 18, 36. Therefore, every number is a factor of itself.
We say every factor is less than or equal to the And ‘1’ is a factor of all numbers.
´
=
´
´
=
,
=
given number. 7 1 7 9 1 9, 13 1 13,...
Greatest factor of a non-zero number is the If a natural number other than ‘1’ has no
number itself. factors except 1 and itself, those numbers are
prime numbers.
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Mathematics In Focus - 8