Question

Find the following using grid models: 

(i) 0.83 + 0.04 

(ii) 0.35 – 0.09

Answer 1

(i) 0.83 + 0.04 

0.83 = \(\frac{83}{100}\) and

0.04 = \(\frac{4}{100}\)

Shading the regions 0.83 and 0.04 

The sum is the total shaded region. 

S = 0.83 + 0.04 

= 0.87

(ii) 0.35 – 0.09

0.35 = \(\frac{35}{100}\) and 

0.09 = \(\frac{9}{100}\)

Shading the regions 0.35 by shading 35 boxes out of 100. Striking off 9 boxes out of 35 shaded boxes to subtract 0.09 from 0.35. 

The left over shaded boxes represent the required value. 

∴ 0.35 – 0.09 

= 0.26