A new armchair costs

1
A new armchair costs 781. Christine has saved
308. How much more does she need to save to buy
the armchair?
2
_______________________

• A new armchair costs 781. Christine has saved
  308. How much more does she need to save to buy
  the armchair?

This is a subtraction sum! 225 - 87
3
_______________________
781
308

• A new armchair costs 781. Christine has saved
  308. How much more does she need to save to buy
  the armchair?

Firstly, put the numbers you are going to use on
the number line.
4
_______________________
2
781
308
310

• A new armchair costs 781. Christine has saved
  308. How much more does she need to save to buy
  the armchair?

Then, count on to the nearest easy number
5
_______________________
2
90
781
308
310
400

• A new armchair costs 781. Christine has saved
  308. How much more does she need to save to buy
  the armchair?

..and again
6
_______________________
2
90
300
781
308
310
400
700

• A new armchair costs 781. Christine has saved
  308. How much more does she need to save to buy
  the armchair?

..keep going..
7
_______________________
2
90
300
80
781
308
310
400
700
780

• A new armchair costs 781. Christine has saved
  308. How much more does she need to save to buy
  the armchair?

..youre not finished yet!..
8
_______________________
2
90
300
80
1
781
308
310
400
700
780

• A new armchair costs 781. Christine has saved
  308. How much more does she need to save to buy
  the armchair?

..one more step..!
9
_______________________
2
90
300
80
1
781
308
310
400
700
780

• A new armchair costs 781. Christine has saved
  308. How much more does she need to save to buy
  the armchair?

..Excellent ! .but are we finished yet?
10
_______________________
2
90
300
80
1
781
308
310
400
700
780

• A new armchair costs 781. Christine has saved
  308. How much more does she need to save to buy
  the armchair?

290300801 (Lets make it easier though
shall we?)
11
_______________________
2
90
300
80
1
781
308
310
400
700
780

• A new armchair costs 781. Christine has saved
  308. How much more does she need to save to buy
  the armchair?

300908021 (Lets make it easier though
shall we?)
12
_______________________
2
90
300
80
1
781
308
310
400
700
780

• A new armchair costs 781. Christine has saved
  308. How much more does she need to save to buy
  the armchair?

300908021 473 (Lets make it easier though
shall we?)