Question

44 × 15 =

• A. 710
• B. 660
• C. 650
• D. 820

Answer 1

Answer:

B. 660

• This method involves breaking one of the numbers into a sum, making the calculation simpler. For 44 × 15, break 15 into (10 + 5).

• Apply the distributive property: a × (b + c) = (a × b) + (a × c). So, 44 × (10 + 5) = (44 × 10) + (44 × 5).

• First, calculate 44 × 10 = 440.

• Next, calculate 44 × 5 = 220. A quick trick for multiplying by 5 is to multiply by 10 and then halve the result (440 / 2 = 220).

• Finally, add the two results: 440 + 220 = 660.

• This technique significantly aids mental calculation and speed during exams.

Method 2: Column Multiplication (Standard Method)

• This is the traditional method taught in schools. Arrange the numbers vertically.

• Multiply 44 by the units digit of 15 (which is 5): 44 × 5 = 220.

• Multiply 44 by the tens digit of 15 (which is 1, representing 10): 44 × 10 = 440. Write this result shifted one place to the left (e.g., align 440 under 220 such that 0 is under 2).

• Add the partial products: 220 + 440 = 660.