Selina Concise Class 6 Math Chapter 5 Natural Numbers and Whole Numbers Exercise 5(B) Solution
(1) Consider two whole numbers a and b such that a is greater than b.
(i) Is a – b a whole number? Is the result always true?
Ans. Yes
(ii) Is b – a a whole number ? Is this result always true?
Ans. No.
(2) Fill in the blanks :
(i) 8 – 0 = _____ and 0 – 8 = _____
8 – 0 ≠ 0 – 8, this shows subtraction of whole numbers is not _______
Ans.: 8, -8, Commutative
(ii) 5 – 10 = ______ which is not a ________
⇒ Subtraction of _______ is not closed.
Ans. -5, whole number, whole numbers.
(iii) 7 – 18 = _______ and (7 – 18) – 5 = ______
18 – 5 = ________ and 7 – (18 – 5) = _______
Is (7 – 18) – 5 = 7 – (18 – 5)?
Ans. -11, -16, 13, -6, They are not equal, Associative.
(3) Write the identity number, If possible for subtraction.
2 – 0 = 2
3 – 0 = 3
4 – 0 = 4
(4) Write the inverse, if possible for subtraction of whole numbers?
Ans. No possible.
(5) 12 x (9 – 6) = 12 x 3 = 36
12 x 9 – 12 x 6 = 108 – 72 = 36
Is 12 x (9 – 6) = 12 x 9 – 12 x 6 = Yes
Is this type of result always true ? = Yes
Name the property used here – Distributive Property.
(6) (16 – 8) x 24 = 8 x 24 = 192
16 x 24 – 8 x 24 = 384 – 192 = 192
Is (16 – 8) x 24 = 16 x 24 – 8 x 24? Yes
Is the type of result always true ? It is only true if y > z
Name the property used here. Distributive property