Level 3 maths addition and subtraction

Show how you solve these number problems.  

1.  Maraea is saving to buy a cat.  In 3 weeks she has saved $9, $56 and $72.

Show how to work out how much she has saved altogether.

9 + 56 + 72.  9 + 50 + 70= 129

6 + 2 = 8 .

129 + 8 = 137

2.  Tom saves his money each month to buy a dog.  In 4 months he has saved $36, $78, $203, and $123.  Show how to work out how much he has saved altogether.

36 + 78 + 203 + 123.  30 + 70 = 100

200 + 100 = 300.  100 + 200 = 300.

6 + 8 = 12.  3 + 23 = 26.  12 + 26 = 38.

38 + 300 = 338.

3.   Te Ao is saving to buy a horse.  So far she has saved $17, $160, $72, and $148.  Show how to work out how much she has saved altogether.

17 + 160 + 72 + 148

150(148 + 2 from 17) + 160 = 310

15 + 70 (72 - 2) = 85 + 2 = 87. 310 + 87 = 897