Maths Mate Sheet 3 Question 23 (Term 3 2014)
Prediction: I predict this will be a problem were I’ll have to complete a sum.
Read: Fill in the missing digits in the subtraction.
Clarification: None needed.
The Big Question: Complete the subtraction.
Mathematician’s Toolbox: Have I seen a similar problem?
Solving: I first worked out the missing digit in the units column would be 1 because 6 minus 5 is 1. Then I figured out that the digit in the tens would be 0 because since you can’t take away 7 from 0 you must borrow to make 10, and 10 take away 7 is 3. Now to work out the last digit you must realize that the 8 is now 7, since the end number has a 4 in the hundreds we know that the last digit must be 3. This is because 7 minus 3 is 4.
Conclusion: So the answer was