Listing down some methods to simplyfy addition.

• Doubles (such as 6 + 6)
• Near doubles: Try adding a double and the remainder. Solve 7 + 6,  (6 + 6+ 1) or (7 + 7 – 1).
• Making a ten or a multiple of 10: To add 7 + 6, I can take 3 from the 6 and put it with the 7 to make 10 and 3. This holds good even with multiples of 10 like 20, 30 40, etc
• 1 more, 1 less: Show problems such as: 8 + 1, 51 + 1, and 6 – 1, 22-1
• Place value Decomposition: 35 + 22 can be decomposed into tens and ones 30+20 added to 5+2. Or 35 – 22 can be decomposed to 30-20 plus 5-2.

Pictorial representation of the strategies above :