Starter quiz
- Which of the following expressions has the same sum as 132 + 16? Can you reason without calculating?
- 130 + 16
- 128 + 20 ✓
- 134 + 18
- 142 + 6 ✓
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- Which of the following expressions has the same difference as 200 − 90? Can you reason without calculating?
- 205 − 95 ✓
- 205 − 85
- 180 − 70 ✓
- 210 − 90
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- Round 14,703 to the nearest multiple of 10
- '14,700' ✓
- Use the correct inequality symbol to make this correct: 234,076 ______ 78,835
- '>' ✓
- What is 17.37 when rounded to the nearest whole number?
- '17' ✓
- Use an efficient strategy to calculate 14,758 + 12,030 = ______
- '26,788' ✓
Exit quiz
- Use rounding, estimating, comparing or reasoning to determine the missing symbol in this inequality statement. 23 + 17 ______ 32 + 28
- '<' ✓
- Use rounding, estimating, comparing or reasoning to determine the missing symbol in this inequality statement. 4.7 + 3.9 ______ 4.9 + 2.5
- '>' ✓
- Use rounding, estimating, comparing or reasoning to determine the missing symbol in this inequality statement. 34,506 + 17,853 ______ 56,231 + 19,106
- '<' ✓
Complete the equation that is represented by the bar model. a + 6,214 = ______- '9,604 + 3,007' ✓
- Balance the equation by finding the unknown value. d + 17.6 = 17.65 + 102 What is the value of d?
- '102.05' ✓
- Balance the equation by finding the unknown value. 14.62 + 18.95 = f + 31.5 What is the value of f?
- '2.07' ✓
Worksheet
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Presentation
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Lesson Details
Key learning points
- If one addend is increased and the other is decreased by the same amount, the sum stays the same.
- If one addend is increased or decreased then the sum increases or decreases by the same amount.
Common misconception
Pupils immediately calculate expressions instead of considering the relationship between expressions.
Take time to model interrogation of values within expressions, identifying relationships between them. Encourage this reasoning and show how it can be more efficient than calculation especially in situations with larger values.
Keywords
Unknown - An unknown is a quantity that has a set value but it is represented by a symbol or letter.
Equation - An equation is used to show that one number, calculation or expression is equal to another.
Expression - An expression contains one or more values, where each value is separated by an operator.
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