Answer :
With Calculator
41.8 = 100%
215%/100% = 2.15
41.8 x 2.15 = 89.87
Without Calculator
41.8 = 100%
x2
83.6 = 200%
/10
4.18 = 10%
/20
2.09 = 5%
200 + 10 + 5 = 215%
83.6 + 4.18 +2.09 = 89.87
41.8 = 100%
215%/100% = 2.15
41.8 x 2.15 = 89.87
Without Calculator
41.8 = 100%
x2
83.6 = 200%
/10
4.18 = 10%
/20
2.09 = 5%
200 + 10 + 5 = 215%
83.6 + 4.18 +2.09 = 89.87