Write a number sentence for: 100 + 20 + 8 = 128 What number comes between? 103 and 105? 139 and 141? 120 and 122? 150 and 148? 146 and 148?

The number is $\boxed{139}$.

3. Write a number sentence for:

• For 100, 40, 9:

$$
100 + 40 + 9 = 149
$$
The number sentence is: $\boxed{100 + 40 + 9 = 149}$

• For 100, 40, 2:

$$
100 + 40 + 2 = 142
$$
The number sentence is: $\boxed{100 + 40 + 2 = 142}$

• For 100, 50:

$$
100 + 50 = 150
$$
The number sentence is: $\boxed{100 + 50 = 150}$

• For 100, 20, 7:

$$
100 + 20 + 7 = 127
$$
The number sentence is: $\boxed{100 + 20 + 7 = 127}$

• For 100, 30, 5:

$$
100 + 30 + 5 = 135
$$
The number sentence is: $\boxed{100 + 30 + 5 = 135}$

4. What number comes between?

• 103 and 105? The number between 103 and 105 is $\boxed{104}$.

• 139 and 141? The number between 139 and 141 is $\boxed{140}$.

• 120 and 122? The number between 120 and 122 is $\boxed{121}$.

• 150 and 148? The number between 150 and 148 (counting down) is $\boxed{149}$.

• 146 and 148? The number between 146 and 148 is $\boxed{147}$.