Question P5–P6 Number × value
Today’s problem — free all day, every step. Every day has one.
A carpenter is making straps for 140 shelf brackets. Each strap needs 65 cm of webbing tape. The tape is sold in rolls of 15 m. How many rolls must the carpenter buy?
Answer
The carpenter must buy 7 rolls. One roll gives 23 complete straps, so 6 rolls give only 138 straps, while 7 rolls give 161 straps, which is enough for all 140 shelf brackets.
One batch repeats. Work out one batch, then multiply.
In this one. Round down when counting complete straps within one roll, then round up when counting whole rolls to buy.
Items are described as a fixed group or ratio that repeats, such as tiles following a pattern, snacks sold in a fixed mix, or a rate given per hour or per item.
Children start from the grand total instead of first working out what one batch is worth. In rate questions they also confuse a duration with a clock time.
Worked examples of all 33 patterns and skills, in a booklet you can print.