Question

16*16=26
23*33=20
25*15=5
18*21=?

Answer 1

Given:

16*16=26

23*33=20

25*15=5

To find:

18*21=?

Solution:

$\to 16-(16-16)\times 1+0\\\to 16-(0)\times 1+0\\\to 16- 0 +0\\\to 16 \\\\\to 33-(33-23)\times 1 +3\\\to 33-(10)\times 1 +3 \\\to 33-10 +3 \\\to 33-13 \\ \to 20 \\\\ \to 15-(25-15)\times 1 +0\\\to 15-(10)\times 1 +0\\\to 15- 10 +0\\\to 5 \\\\\to 21-(21-18)\times 1 +3 \\\to 21-(3)\times 1 +3 \\\to 21- 3 +3 \\\to 21- 6 \\\to 15$

The final value is 15