Ex.1.2 Q4 Integers - NCERT Maths Class 7

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Question

Fill in the blanks to make the statements true:

i) $$(–5) +(–8) = (–8) +(…..)$$

ii) $$–53+……= –53$$

iii) $$17+……= 0$$

iv) $$\begin{Bmatrix} [13+(–12)]+(…..)\\=13 + [(–12)+(–7)]\end{Bmatrix}$$

v) $$\begin{Bmatrix} (–4) + [15+(–3)] \\ = [–4 + 15] +…… \end{Bmatrix}$$

Video Solution
Integers
Ex 1.2 | Question 4

Text Solution

What is known?

Different values

What is unknown?

Missing values

Reasoning:

We have to use different laws of addition.

Steps:

i)
\begin{align}&( {-5}){\rm{ }} + ( {-8}) = ( {-8}) +( {-5})\\&\text{[Commutative law of additions]}\end{align}

ii)
\begin{align}-53 + 0 =-53\text{[Additive Identity]}\end{align}
(adding  to any integer, it gives the same value.)

iii)
\begin{align}{\rm{17 + }}\left( {{\rm{-17}}} \right)\,{\rm{ = 0}}\text{[Additive inverse]}\end{align}

iv)
\begin{align}&\left[ {13 \!+\! \left( -12 \right)} \right] \!+\! \left( {-7} \right) \!=\! 13 \!+\! \left[ {{\rm{ }}\left( {-12} \right){\rm{ }} \!+\! {\rm{ }}\left( {-7} \right)}\right]\\&\text{[Associative law of addition]}\end{align}

v)
\begin{align}& \left( {-4} \right) \!+ \!\left[ {15\!+\! \left( {-3} \right)} \right] \!=\! \left[ {\left( {-4} \right) \!+\! 15} \right] \!+\! \left( {-3} \right)\\&\text{[Associative law of addition]}\end{align}

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