1. To solve problem sums, carefully read the problem, underline keywords, draw a model, number statements and sentences, and check your work. 2. Common models include part-whole, where the whole is found by adding parts or a part is found by subtracting from the whole, and comparison, where the longer amount is found by adding and the shorter by subtracting or their difference is found by subtracting.

1. How to do my Problem Sums?
1. Read carefully
1.Understand 2. Underline Keywords
1. Deal the problem, sentence by sentence
2.Plan 2. Draw model
1. Working
3.Do 2. Number statement and number sentence
1. Look back at the working and tick the
4.Check answers to check.

2. Part-Whole Model
a) To find whole: b) To find part:
 part + part = whole  whole – part = part
? (Whole ) 430 (Whole )
210 196 170 ? (Part)
(Part) (Part) (Part)
c) Part-part-whole:
750 (Whole )
To find whole:
 part + part + part = whole 200 190
To find part: (part) (Part) (part)
Whole – (part + part) = part

3. Comparison Model
a) To find longer bar (whole): b) To find shorter bar(part):
 Add  Subtract
50
?
20
70
100
?
368
c) To find difference between long and short bar:
 Subtract ?
?
To find total of long and short bar:
 Add 250