Solving simple linear equations with an additive step | Maths

Starter quiz

Which equations are represented by this bar model?
- $12 + x = 21$ ✓
- $21 + x = 12$
- $21 − 12 = x$ ✓
- $21 + 12 = x$
- $12 = 21 − x$ ✓
Which equations are represented by this bar model?
- $a + 8 = 33$
- $33 − 8 = a$
- $a = 8 + 33$ ✓
- $33 = a − 8$ ✓
- $8 = 33 − a$
Match each value with its additive inverse.
- $3$
  
  ⇔
  
  $−3$ ✓
- $-3$
  
  ⇔
  
  $3$ ✓
- $1\over 3$
  
  ⇔
  
  $−{1\over 3}$ ✓
- $−{1\over 3}$
  
  ⇔
  
  $1\over 3$ ✓
- $0.3$
  
  ⇔
  
  $−0.3$ ✓
- $10\over 3$
  
  ⇔
  
  $−{10\over 3}$ ✓
Which of these are zero pairs?
- 5 and (−5) ✓
- (−3) and (−3)
- 1 and (−0.1)
- $1\over 2$ and $2$
- $2\over 5$ and $(−0.4)$ ✓
What is the value of the expression $2(3x + 5)$ when $x = −3$ ?
- '−8' ✓
The diagram shows a balanced scale on the left. When an operation is performed to the RHS, it is not balanced. What operation must be performed to the LHS to maintain equality?
- $\times 2$
- $\times 3$
- $+9$ ✓
- $+ 12$
- $+ 18$