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Inverse Practice,
eg:
I'm thinking of a number and when I ... I get ...,
using 1-step calculations:
19 + ... = 40
45 ÷ ... = 5
and 2-step calculations:
7 + ... - 3 = 25
... x 4 ÷ 5 = 8
including ( ) if appropriate:
2(11 + ...) = 36
(36 ÷ 4) ÷ ... = 3
OR
OHS NM3/1a: Missing Numbers |
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-
understand the 4 operations as they apply to whole
numbers & decimals
and
- understand the 4 operations as they apply to whole
numbers & decimals
and
- know how to use the laws of arithmetic & inverse
operations |
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operation
inverse
add, sum, tota
lsubtract, difference
multiply
product
divide
multiple
factor
quotient
divisor
remainder
commutative |
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What
is the cost of 28 Y7 workbooks at £1.99 each?
Use to compare 3 'levels' of efficiency from:
1.99 + 1.99 +1.99 +1.99 + ....to
28 x 1.99
to
30 x 1.99 - 2 x 1.99
Check understanding of multiplication as repeated
addition, but more efficient; 3rd method as an even
more efficient strategy.
Extend to division as repeated subtraction, eg:
using
How many dozen eggs is
156?
(show quotient can be expressed as a remainder,
a fraction or a decimal) |
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Calculations &
simple word problems involving x and ÷, including
opportunities to:
- relate division to fractions
- use commutative law· use distributive law
- use associative law
- check answers by using inverse operations
For a review activity of place value for decimals,
try:
Birmingham
Grid for Numbers from BGfL |
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Use Area calculation
for rectangles to review distributive
law, eg:
L = 13cm
W = 8cm
A = 13 x 8
=10 x 8 + 3 x 8 =...
Use Volume calculation for cuboids to practise commutative
law, eg:
L = 12cm
W = 6cm
H = 2cm
V = 12 x 6 x 2 =... or
6 x 12 x 2 =... or..
(Turn cuboid around to show 3 numbers are interchangeable. |
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'24 Game':
Choose any 4 numbers,use all 4 to make 24,with any
4 arithmetical operations(whole class or in pairs)
Can use for jottings:
WS
NM3/1b: 24 Game Score Sheet |
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- know
& use the order of operations, including
brackets
- carry out calculations with more than 1 step using
brackets & the memory, square root and sign
change keys |
|
order of operations
brackets
calculate
calculation
calculator
display
key
enter
clear
memory |
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Use a string of
numbers on board to demonstrate different answers
with LTR and scientific calculators.
Explain rules of BODMAS.
Use to write some solutions to
24 Game as single expressions (or equations),
eg:
4+ ( 4 X 5 X 1 ) from 1,
1, 4, 5 |
|
1). Investigate
ways of making different totals using same 3 numbers.
Eg: Starting with 2,4 and 5 can you make numbers
1-10? Biggest number? Smallest number? Number nearest
to 0? 10?...
2). Repeat with larger numbers.
3). Collect results on board using rules of BODMAS.
4). Use WS
NM3/1b: 24 Game Score Sheet to allow pupils
to play on pairs. Winning partner writes down their
solution using BODMAS rules.
Extend to larger numbers, squares and square roots. |
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I'm
thinking of a number and when I..., then ... I get
...What number am I thinking of?
Puzzles set by teacher (or individual pupils); pupils
to suggest how to write this down.(linking with
later unit on equations A4) |
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