Number Concepts to 20
Warm-up
Flash a double ten-frame briefly: full left frame plus some on the right. Ask: How many? How did you know? Try quantities 11-19. Ask: What do you always see in the left frame? (Always 10.)
Explore
Pairs roll a number cube, move along a number line 0-20, and say each landing number as ten and ___. When above 10, the ten-frame is full; below 10 it is not. Ask: How many more to reach 20?
Consolidate
Practice
Students build numbers 11-20 on double ten-frames, record them as __ and __, and write the numeral. Exit ticket: show a double ten-frame with 16 and students write the number and say ten and ___.
Exit ticket
Students build numbers 11-20 on double ten-frames, record them as __ and __, and write the numeral. Exit ticket: show a double ten-frame with 16 and students write the number and say ten and ___.
Cover 10 objects and say: I already know there are 10 here. Start from 10 and count the rest: 10 ... 11, 12, 13, ... 17. You counted on from 10 without starting over.
They understand 15 as 10 and 5 but do not know these are written together. Use a place value mat showing tens and ones columns: 15 = 1 ten and 5 ones, written as 15.