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Mathematics in the primary school. The approach to teaching calculation methods. Do it your way!. 25 x 19 5% of 86 248 - 99 103 - 98 ½ of 378 1+2+3+4+5+6+7+8+9+10+11=. Key features of the strategy for mathematics. An emphasis on the development of mental calculation
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Mathematics in the primary school The approach to teaching calculation methods
Do it your way! • 25 x 19 • 5% of 86 • 248 - 99 • 103 - 98 • ½ of 378 • 1+2+3+4+5+6+7+8+9+10+11=
Key features of the strategy for mathematics • An emphasis on the development of mental calculation • A greater focus on the development of number skills and knowledge • Informal methods of calculation until children can…..
Mentally add and subtract anypair of 2-digit numbers • For most children during the latter part of year 3 • Children will be using a variety of mental methods by this time
Mental first • 56+ 29 or 56 29 + • Children stop “saying” the numbers, and start seeing only digits in columns e.g. “6 add 9” instead of “56 add 29”
2000 - 342 - 105 - 102 197 99
25x8 or 25 8 x • Children relying on written procedures forget how much they can do mentally. 25 x 8 is double 25 x 4
The calculating repertoire • Mental recall of number facts • Mental methods of calculation • Use of calculators • Jottings to record mental calculations • Informal written methods • Standard written methods
Expanded Written Methods Standard Written Methods Calculator Mental Calculations with jottings Informal Methods Mental Recall The calculating continuum
The calculating repertoire • Children constantly move up and down the continuum • Learning a new method of calculating does not mean other ways are no longer relevant • Children should always be looking for calculations they can do wholly or partly mentally
A structured approach to calculation An approach based on the skills of mental calculation: • Remembering number facts • Using known facts to derive new ones • Familiarity with the number system and relationships between numbers • Having a repertoire of mental calculation strategies • Understanding of the four operations and how they are related
Addition and subtraction • Partitioning is an important strategy children must learn • A number line is a method of informal calculation that works for any size of number, for both operations. • Knowing 33+ 25 = 58 leads to the following: 25+ 33 = 58 58 - 33 = 25, 58 - 25 = 33 25+ ? = 58 58 = 33 + ?
Multiplication and division • Multiplication is repeated addition, division is repeated subtraction • Doubling, halving, partitioning, and multiplying by 10, 100, 1000 are essential mental strategies • Multiplication and division are the inverse of each other • 3x4=12 leads to 4x3=12; 12÷3=4; 12÷4=3 and then 6x4=24, etc, and then 30x4=120, 300x4=1200, 120÷4=30 etc
Moving from informal to formal methods • At every stage, teachers first use examples that children can easily do mentally • Children then see how the steps in a written procedure link to what they do in their heads • They then move to using numbers that cannot easily be dealt with mentally, Partitioning and place value are crucial concepts and estimation of size of answers is essential.
Now …. • The presentation is over. Next either go to Mr Traynor if your child is in year 3 or 4 or to Ms Buttinger if your child is in year 5 or 6. • We will answer your questions and go into more depth on any of the teaching methods mentioned e.g. grid method, long division, inverse operations, partitioning. • You might want to ask about learning multiplication tables and number bonds, or what does “decomposition” actually mean? • Lastly, there are handouts on the table and workbooks to look at.