In this lesson, we will learn how to use different strategies to add two numbers with sums up to 20 and choose which strategies are best.
Q1:
Calculate 5+8.
Q2:
James and Hannah are trying to find 8+9.
James uses the fact that 8+8=16 and says that 8+9=16+1.
Hannah uses the fact that 9+9=18 and says that 8+9=18−1.
Who is correct?
Q3:
Think about adding 8 and 7.
One of the equations is WRONG. Which one is it?
Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.