Chapter 3

The World of Numbers

CBSE Class 9

Mathematics Solutions

Question:

Calculate the following using Brahmagupta's laws:

(A) (-12) × 5

(B) (-8) × (-7)

(C) 0 - (-14)

(D) (-20) ÷ 4 [Page No. 46]

Answer: Verified

(A) (-12) x 5 = -60 (debt x fortune = debt)

(B) (-8) x (-7) = 56 (debt x debt = fortune)

(C) 0 - (-14) = 0 + 14 = 14 (0 - debt = fortune)

(D) (-20) ÷ 4 = -5 (debt ÷ fortune = debt)

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(All Q's of this Chapter solved)

More NCERT Questions

Try to extend this method for constructing line segments of lengths sqrt(3) and sqrt(5) using a ruler and a compass. Generalise this method to construct a line segment of any length of the form sqrt(n Consider this puzzle: What is the square root of -1? We know that 1 × 1 = 1. We also know that (-1) × (-1) = 1. There is no real number that, when multiplied by itself, results in a negative number. T The decimal expansion of p/q will be terminating precisely when the prime factors of q are only 2, only 5, or both 2 and 5. Can you explain why? [Page No. 58] Try to find the decimal expansions of 10/3 and 11/12. What do you observe about the repetition of the digits after the decimal point? [Page No. 57]