Explain 81-16 in mental math

Question

asked Aug 25, 2019 30.8k views

2 Answers

Praveen Prajapati · Answer 1 · 2019-08-26T07:44:24+0000

Answer:

65 See below

Explanation:

when doing mental math you need to break it apart to more manageable chunks.

I would think of this as 70 and 11 - 6 = 75 then subtract 10 = 65

Sohail Hameed · Answer 2 · 2019-08-30T18:45:46+0000

Answer:

we have

(81-16)

One way to use mental math is to add 4 to both 81 and 16

so

81+4=85\\ 16+4=20\\ 85-20=65

therefore

81-16=65

the answer is

65

Explanation: