Teaching and Group Activities for Understanding
Day 1 Teaching
Draw a line from 0–100 with only 0 and 100 land no other marks. Where can we mark 47? Discuss how it is helpful to mark 50. Then discuss how to place other numbers and agree that marking all multiples of 10 is helpful to locate other numbers. Then play ‘guess my number’ with two children forming the ends of the 0–100 line.
-- Sketch number lines; estimate the position of 2-digit numbers between 0 and 100 as accurately as possible.
-- Estimate the value of mystery numbers on a 0–100 sketched line by considering nearby 10s.
Day 2 Teaching
Display 0–10 number line (see resources), point to 3 and ask: Is this closer to 0 or 10? Repeat for other numbers. Explain that we call this ‘rounding to nearest ten’. Spend time talking about 5, explaining that, although it is in the middle, we always round up to the 10 above. Repeat for numbers between 30 and 40, to include 35.
Use the in-depth problem-solving investigation ‘Which scripts?’ from NRICH as today’s group activity.
Or, use these activities:
-- Mark 2-digit numbers on a line; round to nearest 10. Create a poster to explain rounding.
-- Play ‘Rounding Pelmanism’.
Day 3 Teaching
Show a 101–200 square (see resources). Count from 101 to 200, pointing at the numbers and noting they follow the same patterns as 1 to 100. Show a 0–100 beaded line. How could we change this 0–100 beaded line to be a 100–200 beaded line? Amend 0 to 100, 100 to 200. What should we change 10 to? And 20? etc. Count in 10s from 100 to 200. Mark on various 3-digit numbers to 200.
-- Order 3-digit numbers between 100 and 200; locate on a beaded or landmarked line.
-- Place 3-digit numbers on a landmarked line.