Number Bonds Answer Boards are an easy way for children to display their answers. Sturdy answer boards are ideal for small group or whole class number bond activities. Answer boards are an ideal way to get shy children involved in classroom activities. Hand-held boards are double-sided: Blank number bond on one side and space to write fact families on the reverse.Number bonds are ideal for practising a variety of maths concepts: Addition and subtraction Inverse operations and number relationships.The wipe-clean boards can be used time and time again and works with wet- or dry-erase markers.Board faces measure 16cm H x 16cm W.