Question 3 State whether the following number sentence is true or false. 3.1.1 9−3=3−9 3.1.2 29−12=(20+9)−12

Since $6 \neq -6$, the statement is false.

$$\boxed{\text{False}}$$

3.1.2) State whether the following number sentence is true or false: $29 - 12 = (20 + 9) - 12$

First, perform the operation inside the parentheses.

$$(20 + 9) - 12 = 29 - 12$$

Since $17 = 17$, the statement is true.

$$\boxed{\text{True}}$$