Page 10 - SM inner class 6.cdr

E xercise 1.2

1. Round off the follow ing numbers to the near est tens:
(i) 89 (ii) 415 (iii) 3951 (iv) 4409

2. Round off the follow ing numbers to the near est hundreds:
(i) 695 (ii) 36152 (iii) 13648 (iv) 93618
3. Round off the follow ing numbers to the near est thou sands:
(i) 3415 (ii) 70124 (iii) 8765 (iv) 4001

4. Round off each of the follow ing numbers to the near est ten thou sand:
(i) 1496981 (ii) 3568107
5. Round off each of the follow ing numbers to the near est lakh:
(i) 2537981 (ii) 14381507
6. Esti mate the sum 1,472 + 22,398 + 14,772 + 18,164 by round ing each number to the near est thou sand.
7. Esti mate the prod ucts of 331 and 267 by round ing to the near est ten.

8. Medi cine is packed in boxes, each weigh ing 5 kg 200g. Esti mate that how many such boxes can be
loaded in a van which cannot carry beyond 260 kg?
9. A student multiplied 1234 by 32 instead of multiplying by 23.Estimate that by how much was his
answer greater than the correct answer?
10. A merchant had ` 88,592 with him. He placed an order for purchas ing 50 radio sets at ` 1100 each. Esti -
mate that how much money will remain with him after the purchase?

Roman Numerals There are a few rules for writing numbers with
Roman numerals.
The way we write numbers, using
Hindu-Arabic numerals, is hardly the only 1. Repeating a numeral (up to three times)
way to do so. Many civilizations used other represents addition of the number.
means to denote numbers.
For example, III represents 1 + 1 + 1 = 3.
For example, the Romans represented
2. Only I, X, C, and M can be repeated; V, L,
numbers using the numerals I, V, X, L, C, D,
and D cannot be, and there is no need to
and M. These numerals represent the
do so.
following numbers:
3. Writing numerals that decrease from left
Roman Numeral Hindu-Arabic Equivalent
to right represents addition of the
I 1 numbers.

V 5
For example, LX represents 50 + 10 = 60
X 10
and XVI represents 10 + 5 + 1 = 16.
L 50
4. Writing a smaller numeral to the left of a
C 100
larger numeral represents subtraction.
D 500
For example, IV represents 5 - 1 = 4 and
M 1000 IX represents 10 1 9. To avoid
-
=
ambiguity, the only pairs of numerals
that use this subtraction rule are:

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Mathematics In Focus - 6