Practice30Create account

Deepa believes that changing the order in a subtraction does not change the answer. She works out 84 - 27 and then 27 - 84. By how much do her two answers actually differ?

Class 6Whole NumbersWhole Numbers
  • A0, because the two answers are the same
  • B57
  • C111
  • D114

Step-by-Step Solution

84 - 27 = 57, while 27 - 84 = -57. The two results differ by 57 - (-57) = 114, so they are certainly not equal. Subtraction is NOT commutative; only addition and multiplication of whole numbers are. Answering 111 comes from adding 84 + 27 instead of subtracting.
Answer: D) 114

Key idea: Properties of whole-number addition and multiplication

**Commutative**: a + b = b + a, and a × b = b × a. Order does not matter for addition or multiplication.

**Associative**: (a + b) + c = a + (b + c), and (a × b) × c = a × (b × c). Grouping does not matter.

**Distributive**: a × (b + c) = a × b + a × c. Multiplication 'distributes over' addition. This is one of the most useful rules in all of maths.

**Identity**: a + 0 = a (zero is the additive identity), and a × 1 = a (one is the multiplicative identity).

**Multiplying by zero**: a × 0 = 0 for every whole number a.

Master this chapter in 30 minutes a day.

Don't just memorise the answer — build a daily practice habit.

Practice 5 Similar Questions Free →

All Whole Numbers practice questions

More Class 6 Whole Numbers practice

Which of these statements is NOT true for all whole numbers a, b and c?A vendor in Surat sold goods worth 648 rupees on Monday, 275 rupees on Tuesday and 352…Find 25 × 36 × 4 by regrouping the factors sensibly. What is the product?Use the distributive property to find 47 × 98.Simplify without a calculator: 48 × 67 + 48 × 33.