Sonu is measuring some of his body parts. The length of Sonu’s lower arm. Class 7

Sonu is measuring some of his body parts. The length of Sonu’s lower arm. Class 7

Question 1.

Sonu is measuring some of his body parts. The length of Sonu’s lower arm is 2[latex]\frac{7}{10}[/latex] units, and that of has upper arm is 3[latex]\frac{6}{10}[/latex] units. What is the total length of his arm? Class 7

Solution:

Total length = (2[latex]\frac{7}{10}[/latex] + 3[latex]\frac{6}{10}[/latex])units

= (2 + 3 + [latex]\frac{7}{10}[/latex] + [latex]\frac{6}{10}[/latex])units

= (5 + [latex]\frac{13}{10}[/latex])units

= (5 + 1[latex]\frac{3}{10}[/latex])units

= 6[latex]\frac{3}{10}[/latex]units

Question 2.

As in the case of counting numbers, it is convenient to start subtraction from the tenths. We cannot remove 7 one-tenths from 4 one-tenths. So we split a unit from 12 and convert it to 10 one-tenths. Now, the number has 11 units and 14 one-tenths. We subtract 7 onetenths from 14 one-tenths and then subtract 6 units from 11 units. Class 7

Try computing the diffrence by converting both lengths to tenths.

Solution:

12[latex]\frac{4}{10}[/latex] = [latex]\frac{12 \times 10}{10}[/latex] + [latex]\frac{4}{10}[/latex]

= [latex]\frac{120}{10}[/latex] + [latex]\frac{4}{10}[/latex] = [latex]\frac{124}{10}[/latex]

and, 6[latex]\frac{7}{10}[/latex] = [latex]\frac{6 \times 10}{10}[/latex] + [latex]\frac{7}{10}[/latex]

= [latex]\frac{60}{10}[/latex] + [latex]\frac{7}{10}[/latex] = [latex]\frac{67}{10}[/latex]

So, 12[latex]\frac{4}{10}[/latex] - 6[latex]\frac{7}{10}[/latex] = [latex]\frac{124}{10}[/latex] - [latex]\frac{67}{10}[/latex] = [latex]\frac{124-67}{10}[/latex] = [latex]\frac{57}{10}[/latex]

= [latex]\frac{50+7}{10}[/latex] = [latex]\frac{50}{10}[/latex] + [latex]\frac{7}{10}[/latex] = 5 + [latex]\frac{7}{10}[/latex]

= 5[latex]\frac{7}{10}[/latex]units