how to subtract 86 and 47 in your head?

Answer 1

I add 40 to 47 and get 87. I'm one over, so I subtract one from 40.
39.

Answer 2

If you mean 86 - 47 =

mentally round 47 up to 50 (remainder 3), 50 from 86 =36, add the 3 you left off to make 39.

Answer 3

Add 1 to 86 (87). Then do 87-47 = 40. Subtract 1 and get 39.

Answer 4

I do it in two stages.

The problem is 86-47.

47 is close to 46. I can figure out that 86 - 46 is 40 in my head very quickly.

However, 47 is one more than 46, so I know that the answer to the original problem will be one less than the estimate (40), thus the answer is 39.

There are many ways to simplify this problem. This is just how I did it.

Answer 5

For subtracting 86, normally I will subtract 80 first, and then subtract 6 later, or I will subtract 90 and add 4 later, up to the situation.

It is the same I will do for subtracting 47.

Answer 6

something is right.
Subtract 47 from 87. This is easier and can be done mentally. You get 40.
Since you started out with 86, one less than 87, so subtract 1 from your answer.
You get 39

Answer 7

I actually do it similar to something except I do it in reverse,

86 - 47.

86+1=87

87-47=40

40-1=39

Answer 8

What I will do is

86 + 1 (in my mind now is 87 )

then 87 - 47 give me 40

40 minus 1 will give me 39

Answer 9

count backwards by 10's then subtract the remaner 7

Answer 10

I draw out the problem in my head. It's not that hard.